What Size Light Bulb for Lamp: Practical Guide for 2026

The Vgogfly A15 LED bulb 4-pack is an energy-conscious replacement bulb engineered with a standard E26 medium screw base and a compact physical profile. Drawing just 3 watts while offering the illumination equivalent of a traditional 25-watt incandescent bulb, this set is well suited for homeowners, renters, and families outfitting bedside nightstands, multi-socket ceiling fans, and small accent fixtures throughout the home.

Lighting performance centers on a comfortable 2700K warm white color profile coupled with an output of 450 lumens per bulb. The unit provides a wide 240-degree beam angle, allowing the soft white light to disperse broadly across a room, desk, or reading nook rather than casting a narrow downward spotlight. Because the output is tuned to 450 lumens, it serves effectively for relaxing ambient illumination, evening reading, or multi-bulb ceiling fixtures where several low-wattage bulbs work together without overpowering the space.

In terms of physical construction, each bulb features a compact A15 bulb shape measuring 1.76 inches wide and 3.46 inches tall. The housing utilizes a specialized plastic mask designed to accommodate the thermal dissipation requirements of the internal LED chips. Its standard E26 base threads cleanly into 120V household sockets, ensuring a firm mechanical fit across tabletop reading lamps, enclosed or semi-enclosed ceiling fan bowls, and compatible household appliances.

Everyday setup is simple, requiring only a straightforward screw-in installation into any standard 120V E26 socket. The modest dimensions prevent the bulb from protruding beyond compact lamp shades or ceiling fan glass covers, which is a frequent challenge with standard A19 bulbs. With a low 3-watt energy draw, running these bulbs for extended daily hours across kids rooms, living areas, or hallway fixtures maintains light availability while keeping total electrical load minimal.

Buyers should keep a few realistic limitations in mind before purchasing. The product data does not list dimming support, meaning these bulbs should only be used in standard on/off circuits and will not pair properly with wall dimmers or variable-intensity switches. Furthermore, with an output of 450 lumens per bulb and a fixed 2700K color profile, they are not intended for high-intensity task work or crisp daylight settings, nor do they feature smart connectivity for voice or app automation.

For shoppers seeking a low-wattage solution for ceiling fans, nightstands, and small decorative lamps, the Vgogfly 4-pack offers practical everyday utility. Confirming your fixture requires a 120V E26 base and benefits from a compact A15 bulb shape ensures this soft white set delivers dependable, gentle illumination right where you need it.

These bulbs feature an E26 medium screw base, which is the standard socket size found in the vast majority of residential lighting fixtures across the United States. Designed for 120V electrical systems, they screw directly into everyday table lamps, floor lamps, ceiling fans, and wall sconces without requiring adapters or socket converters.

Because they utilize the compact A15 form factor measuring 1.76 inches by 3.46 inches, they provide significant physical clearance advantages over traditional A19 bulbs. This makes them particularly practical for ceiling fan light kits, small nightstand lamps, or compact appliance sockets where standard-sized bulbs are too tall or wide to fit within the decorative shade or glass enclosure.

Each Vgogfly bulb produces 450 lumens while consuming only 3 watts of power, functioning as a direct energy-efficient replacement for a standard 25-watt incandescent bulb. The 2700K soft white color temperature provides a warm, golden-toned glow that creates a cozy and restful atmosphere in living rooms, bedrooms, and dining spaces.

The bulb distributes its light output across a wide 240-degree beam angle. This broad beam spread minimizes directional hotspots and harsh shadows, ensuring even illumination across a desk or bedside table. Because dimming capability is not specified in the manufacturer data, these bulbs should be installed in standard on/off fixtures rather than circuits wired to dimming switches.

The TJOY A19 60-Watt Equivalent LED Light Bulb 6-pack is an entry-level retrofit solution designed for general residential and light commercial illumination. Utilizing an energy-conscious 9-watt draw on a standard medium E26 screw base, this bulb pack targets homeowners, renters, dorm residents, and rental property managers wanting to reduce electricity use without rewiring or changing fixtures. It is best suited for bedside lamps, floor lamps, ceiling fans, entryways, and hallways where simple, switched lighting is required.

In terms of real-world lighting output, each bulb generates 800 lumens, matching the standard light levels expected from a traditional 60-watt incandescent bulb. The 2700K color temperature casts a warm, soft white tone that promotes a relaxing environment in living rooms, dining spaces, and bedrooms. With an 80 CRI rating, colors appear clear and balanced for day-to-day living activities. The product specifications also indicate non-flickering and non-dazzling performance, which helps reduce visual strain during evening reading and family activities.

Regarding physical design and safety, each bulb adheres to classic A19 sizing, measuring 2 inches in diameter and 4 inches in length. This standard footprint prevents clearance problems inside common glass shades, recessed bowls, or narrow lamp harps. From a safety standpoint, the bulbs contain no mercury or lead and emit no infrared radiation. They hold official UL Listing, RoHS conformity, and FCC certification, confirming compliance with rigorous electrical construction and radio frequency standards in the United States.

Setting up these bulbs requires nothing more than screwing them into an existing E26 medium socket while the fixture switch is off. Because these units are strictly non-dimmable, they should be connected only to regular on/off switches. Installing them on a dimming circuit can cause buzz, audible humming, or early driver failure. When paired with standard on/off power controls, they illuminate immediately to full brightness without warmup intervals, carrying a manufacturer-rated service life of up to 13.7 years under an assumed 3-hour daily operational schedule.

Buyers should keep in mind the clear functional limitations before purchasing. These bulbs cannot be dimmed, offer no smart-home app connectivity, and feature a fixed 2700K warm white hue that may feel too warm for detailed garage work or task-focused home office desks. However, for buyers needing an affordable, UL-certified, 6-pack of standard 60-watt equivalent replacement bulbs for everyday lamps and ceiling fixtures, this package offers straightforward reliability and exceptional operating value.

Each TJOY A19 bulb outputs 800 lumens of light while drawing only 9 watts of electrical power. This matches the brightness level of a standard 60-watt incandescent bulb while reducing energy consumption by approximately 85 percent.

Based on a standard usage assumption of 3 hours per day, the manufacturer estimates the operating cost at roughly $1.08 per bulb per year. This makes upgrading multiple lamps and ceiling lights throughout an apartment or house an efficient step toward lowering household utility costs.

The 2700K Kelvin rating places these bulbs firmly in the soft warm white lighting category. This warm appearance produces a calm, golden-amber undertone that helps soften interior rooms, making it a natural fit for living rooms, bedrooms, and dining spaces.

The Color Rendering Index is rated at 80 CRI. While specialized photography or art studio tasks often call for 90+ CRI, an 80 CRI rating is fully adequate for domestic living areas, ensuring that home furnishings, clothing, and wall paint look vibrant and true to life.

These bulbs use the ubiquitous E26 medium screw base, which is the standard socket size across American household lamps, pendant lights, ceiling flush-mount fixtures, and wall sconces.

With physical dimensions of 2 inches by 4 inches, they retain standard A19 sizing. This ensures smooth replacement inside enclosed globes, open vanity bars, and table lamps without clearance issues or protruding awkwardly beyond the shade.

Safety credentials include a UL Listing along with FCC and RoHS certifications, verifying that the internal electrical components meet recognized North American fire and shock safety criteria.

TJOY covers these A19 LED bulbs with a 1-year after-sales service policy. The manufacturer provides prompt replacement or refund support for any product defects encountered within the first year of ownership.

The OHLGT 15-Watt Salt Lamp Light Bulb 6-pack is an incandescent replacement bulb set engineered specifically for Himalayan salt lamps, basket fixtures, and accent lights equipped with an E12 candelabra socket. Unlike general household illumination where heat is avoided, authentic rock salt lamps rely on the gentle thermal output of an incandescent filament to function as intended. Homeowners, apartment residents, and ambient lighting enthusiasts will appreciate this multi-pack for easily maintaining their decorative salt fixtures without compatibility guesswork.

Lighting performance centers on a soothing, warm yellow light output that complements the natural mineral tones of rock salt sculptures. Operating at 15 watts, each bulb produces a subtle, glare-free radiance suitable for bedrooms, living rooms, yoga areas, and home offices. When installed in a salt lamp cord featuring an integrated dimmer dial, these bulbs support smooth manual dimming, allowing users to transition easily from a brighter accent glow during the day to a soft night-light level in the evening.

Physical construction incorporates a lead-free E12 screw base built for standard 110V to 120V North American electrical fixtures. With overall measurements of 0.86 inches in diameter and 2.16 inches in total length, the compact glass profile easily slides through narrow openings in salt rock bases and metal baskets. The manufacturer rates each incandescent bulb for approximately 1,000 hours of operating life, delivering a reliable balance of steady warmth and illumination under normal operating conditions.

Setup and replacement require only standard bulb installation practices. Users simply thread the E12 base clockwise into their existing salt lamp cord assembly or clip-in socket until secure. Routine replacement should always be performed with the fixture disconnected from wall power and after the previous bulb has cooled completely. The multi-pack format ensures that owners have backups ready, reducing downtime when an original factory bulb eventually reaches the end of its filament life.

Buyers should keep realistic limitations in mind prior to purchasing. As an incandescent product, each bulb consumes 15 watts and produces noticeable radiant warmth, which means these bulbs are not suitable for enclosed fixtures requiring cool-touch illumination or high energy savings. Furthermore, these bulbs do not feature built-in smart controls or standalone dimming hardware, meaning dimming is entirely dependent on an external dimmer switch present on the fixture cord or wall.

For owners of Himalayan salt lamps who need authentic replacement bulbs that produce both mood-setting amber light and essential warmth, the OHLGT 15-Watt E12 6-pack provides dependable compatibility. It delivers a direct physical and electrical fit for standard salt lamp assemblies at an accessible everyday value.

The OHLGT replacement bulbs feature a standard E12 candelabra screw base tailored for 110V to 120V North American electrical circuits. This base sizing matches the standard socket diameter found in most Himalayan salt lamp cords, clip-in metal assemblies, and decorative night lights.

With physical dimensions of 0.86 inches in width and 2.16 inches in height, each bulb is shaped to fit inside compact salt rock cavities. Buyers should confirm their fixture requires an E12 candelabra base rather than larger intermediate E17 or standard household E26 sockets before installing.

These 15-watt incandescent bulbs support variable light adjustment only when installed in fixtures with an external dimmer switch. The bulbs do not contain onboard dimming electronics, so constant-voltage non-dimming cords will run the bulbs at full brightness.

Unlike solid-state LED alternatives, these incandescent filaments intentionally disperse gentle thermal warmth during operation. This heat transfer is a necessary feature for Himalayan salt lamps to function properly and prevent excessive moisture buildup on the rock surface.

The Briignite 3-Way LED Light Bulb 2-pack is engineered specifically for table lamps, floor lamps, and reading fixtures outfitted with multi-level 3-way sockets. For households looking to replace energy-draining incandescent or sluggish compact fluorescent (CFL) options, this set delivers adjustable room illumination tailored for living rooms, bedrooms, and home offices. It allows users to cycle between relaxing low light and bright task lighting with a twist of the lamp switch.

Lighting output is divided across three practical settings: low (500 lumens at 7 watts), medium (1000 lumens at 10 watts), and high (1500 lumens at 15 watts), designed to match traditional 50-watt, 100-watt, and 150-watt incandescent bulbs. Rated at a 3000K warm white color temperature with an 85+ CRI (Color Rendering Index), the light provides a welcoming ambiance while rendering interior decor and reading materials clearly. Unlike CFL alternatives, these bulbs deliver instant-on brightness with no delayed warm-up period.

Constructed with a durable, non-glass body, each bulb measures 2.36 inches wide by 4.65 inches high, easily fitting inside common lamp harps and shades. The design eliminates fragile glass that can shatter during replacement and contains no mercury, lead, or UV radiation. With a manufacturer-rated lifespan of 15,000 hours, these LED units offer dependable, long-lasting performance while cutting energy usage by up to 85 percent compared to classic 150-watt incandescent lamps.

Fixture compatibility requires careful attention before purchase. These bulbs are designed exclusively for standard 3-way lamp sockets. According to product specifications, they should not be installed in touch-sensitive lamps, fixtures controlled by wall dimmers, or standard single-setting switches. Using them with dimmer switches can cause operational buzzing or noise, while conventional switches prevent switching between tiers, locking output to a single brightness setting.

For homeowners, renters, and families wanting an efficient upgrade for their dual-contact 3-way lamps, the Briignite 3-Way LED bulbs offer great practical value. As long as you confirm your lamp features a true 3-way rotary socket rather than a touch or dimmer control, this 2-pack delivers reliable multi-level brightness and crisp warm white ambiance for daily relaxation and focused reading.

The Briignite 3-Way LED bulb features three distinct output levels designed to match traditional multi-setting incandescent options. The low setting consumes 7 watts and emits 500 lumens, serving as an energy-efficient equivalent to a 50-watt incandescent bulb for subtle ambient illumination or evening relaxation.

The medium setting draws 10 watts to produce 1000 lumens, matching the output of a 100-watt bulb for everyday room lighting and casual tasks. The high setting uses 15 watts to generate 1500 lumens, matching a 150-watt bulb to provide bright, focused illumination for reading or detailed work.

This bulb is engineered strictly for dedicated 3-way lamp sockets that feature dual electrical contacts at the base. It relies on the fixture's internal switching mechanism to alternate power between the individual LED circuits that generate 500, 1000, and 1500 lumens.

It is not compatible with touch-activated lamps, wall dimmers, or electronic dimming controls, which can cause buzzing noises and erratic performance. When placed in a conventional single-circuit on/off switch, the bulb cannot cycle through its multi-level stages and will operate at a fixed brightness level.

The Brightever A19 LED Light Bulbs come in a convenient 4-pack designed for standard household lighting upgrades, serving as an energy-efficient replacement for traditional 100-watt to 125-watt incandescent bulbs. Consuming just 13 watts of electricity, these non-dimmable bulbs appeal to homeowners, renters, and apartment residents who want to lower energy usage without sacrificing brightness. They are well suited for task-driven spaces such as home offices, kitchens, laundry rooms, basements, and workshops where clear, immediate visibility is essential.

In terms of lighting performance, each bulb outputs 1500 lumens paired with a 5000K daylight white color temperature. This cool, daylight-toned illumination creates an active, clean environment suitable for reading, cooking, and detail-oriented projects. A major advantage highlighted by the manufacturer is the 90+ Color Rendering Index (CRI), which ensures household objects, food, and painted surfaces appear vibrant and true to life. Additionally, the wide 280-degree beam angle casts a broad blanket of light, helping eliminate dark corners when installed in ceiling pendants, vanity lights, or multi-socket fixtures.

The build design features a standard A19 bulb profile measuring 2.36 inches in diameter and 4.57 inches in length. Outfitted with an E26 medium screw base (26mm diameter), the bulb fits seamlessly into common American light sockets. Brightever emphasizes eye comfort, engineering the internal electronics to prevent flicker, strobe, and glare. The construction is also free of toxic lead and mercury, does not emit UV or IR radiation, and incorporates heat-dissipating components rated to deliver over 25,000 hours of operating life.

Installation is completely straightforward and requires no tools or wiring adjustments. You simply thread the E26 base into any compatible table lamp, desk lamp, floor lamp, chandelier, wall sconce, or ceiling fan. While the product details state suitability for indoor and outdoor applications such as porches, patios, and entryways, buyers should ensure exterior fixtures are adequately enclosed and shielded from direct moisture, as no specific IP water-resistance rating is supplied.

Before purchasing, buyers must take note of two key operational limits. First, these bulbs are strictly non-dimmable; connecting them to a dimmer switch or dimming socket can cause buzzing, blinking, or driver damage. Second, the 5000K color profile provides a cool, clinical clarity that may not match spaces where soft, warm, relaxing light is desired, such as cozy bedrooms or low-lit dining areas.

For consumers seeking a bright, cost-effective replacement for older high-wattage incandescent bulbs, the Brightever 13W A19 pack delivers dependable everyday utility. With its strong 1500-lumen output, clean 5000K daylight hue, 90+ CRI color fidelity, and wide 280-degree light distribution, this 4-pack serves as a practical, high-value choice for task areas and high-use household fixtures.

Each Brightever A19 bulb generates 1500 lumens of light output while drawing only 13 watts of electrical power. This output is designed to match the brightness of a standard 100-watt to 125-watt incandescent bulb, providing substantial light distribution for open rooms and task areas.

The color temperature is rated at 5000K daylight white, creating a clean, energizing light quality well suited for kitchens, home offices, and study desks. Backed by a 90+ CRI rating, the light accurately renders colors, preventing the dull or gray appearance often associated with lower-CRI LED alternatives.

A broad 280-degree beam angle ensures light is cast evenly across large areas. Furthermore, the stable electronic design operates without flicker or strobe, helping reduce eye strain during prolonged reading or focused work sessions.

These bulbs utilize an industry-standard E26 medium screw base measuring 26mm in diameter. This makes them physically compatible with standard household sockets found in table lamps, floor lamps, wall sconces, pendants, chandeliers, and ceiling fan fixtures across the United States.

The physical dimensions measure 2.36 inches wide by 4.57 inches tall, matching standard A19 proportions to ensure a clean fit inside lamp harps, shades, and decorative glass enclosures.

Because these bulbs are non-dimmable, they must be used on standard on/off circuits only. When using them outdoors around porches, patios, or entryways, install them inside weather-tight, enclosed fixtures to protect the electrical base from moisture exposure.

The Sphoon G40 1.5W LED bulb is a specialized, low-output accent light designed for standard household fixtures that require soft illumination rather than harsh brightness. Featuring a compact globe silhouette and an E26 medium screw base, this two-pack is an ideal solution for homeowners, renters, and apartment dwellers looking to outfit bedside nightstands, decorative chandeliers, accent lamps, or compatible household appliances like refrigerators and range hoods.

Lighting performance centers on gentle illumination and warm visual comfort. Producing 150 lumens at a 2700K soft warm white color temperature, each bulb provides a soothing, low-glare glow that mimics traditional low-wattage incandescent filaments. With a color rendering index (CRI) rated at greater than 95, this bulb renders interior colors, wood finishes, and decor with exceptional accuracy, making spaces feel inviting rather than washed out.

Physical construction pairs a classic G40 globe shape with frosted glass to evenly disperse light from the interior LED filament. Measuring approximately 1.57 inches in diameter and 2.36 inches in total length, the compact footprint fits easily into shallow lamp shades, exposed-socket string setups, and enclosed appliance compartments. Operating on standard 120V electrical circuits, each bulb consumes just 1.5 watts while delivering brightness comparable to a traditional 15-watt incandescent bulb.

Routine installation is as straightforward as threading any standard light bulb. You simply turn off power to the fixture and screw the E26 base into the socket until snug. The manufacturer rates the operating lifespan at 25,000 hours, which significantly reduces the frequency of replacements in hard-to-reach ceiling fixtures, delicate decorative chandeliers, or everyday bedside lamps.

Buyers should evaluate specific practical limitations before purchasing. At 150 lumens, these bulbs are deliberately dim and will not serve as adequate primary lighting for reading rooms, general kitchen task areas, or large workshops. Furthermore, the manufacturer specifications do not indicate dimmer switch compatibility, so installing them on standard non-dimming switches is advised to prevent potential buzzing or irregular light output. While suitable for protected patio or balcony fixtures, outdoor installations require weather-shielded sockets.

Overall, this Sphoon G40 LED bulb pack is a smart, targeted purchase for anyone needing low-wattage, high-CRI accent lighting on a standard E26 socket. It delivers the warm aesthetic of vintage globe bulbs with minimal power consumption, making it an excellent match for cozy bedrooms, ambient dining spaces, and practical appliance lighting.

This bulb is engineered with a standard E26 medium screw base, which is the most common socket size in American household lighting. It screws directly into standard 120V table lamps, wall sconces, hanging pendant cords, and compatible home appliances.

Despite its compact G40 mini-globe size of 1.57 inches wide by 2.36 inches long, it does not use a smaller candelabra base. Buyers should verify that their lighting fixture or appliance requires a standard medium E26 socket rather than an E12 socket before installation.

Each bulb generates 150 lumens of low-intensity light, intentionally engineered for ambient, decorative, or nightstand use where standard 800-lumen household bulbs cause uncomfortable glare. This output serves as an efficient equivalent to a traditional 15-watt incandescent bulb.

The 2700K color temperature produces a classic soft warm white glow, supported by a CRI rating over 95. This high color rendering index helps fabrics, paints, and room furnishings look natural and rich under warm evening lighting conditions.

Drawing only 1.5 watts of electrical power on standard 120-volt circuits, this LED bulb cuts energy consumption by more than 85 percent compared to the 15-watt incandescent bulbs it replaces. This low power draw makes it economical to leave on as a hallway night light or decorative ambient accent.

With a manufacturer-listed lifespan of 25,000 operating hours, these bulbs offer long-term service without frequent maintenance. That extended durability is particularly helpful when used inside refrigerator compartments, range hood vents, or elevated decorative fixtures.

The Briignite A19 LED Grow Light Bulb 2-Pack offers a clean and practical lighting solution for indoor gardening enthusiasts, apartment renters, and home-office growers. Designed to fit standard household lighting fixtures, this product provides an accessible entry point for nurturing herbs, leafy greens, seed starts, and tropical houseplants. Rather than requiring bulky ballasts, external drivers, or dedicated horticultural frames, this bulb uses the ubiquitous A19 profile to bring targeted plant lighting right to your existing living spaces.

In terms of real-world lighting output, each bulb produces a listed 1000 lumens of brightness while drawing just 11 watts of electricity. The manufacturer rates this performance as equivalent to a traditional 100-watt incandescent bulb. What sets this model apart from conventional grow lamps is its visual appearance: it emits a balanced 4000K neutral white light that integrates comfortably into home decor, while internally providing the essential red and blue spectrum wavelengths plants require. With a wide 180-degree beam spread and a rated photosynthetic photon flux (PPF) of 25 micromoles per second, it provides reliable light absorption across all growth stages without flooding the room in distracting magenta or purple lighting.

Build quality centers on functional thermal management and standard residential durability. The bulb combines aluminum and plastic in its housing structure to facilitate passive heat dissipation. Controlling surface temperatures is critical for plant health, as excessive ambient heat can dry out soil or scorch delicate foliage. According to the manufacturer, this cooling design contributes to an overall rated lifespan of up to 25,000 hours, offering steady day-to-day operation through multiple growing cycles.

Installation is completely straightforward. The standard E26 medium screw base fits standard desk lamps, gooseneck reading fixtures, pendant cords, or floor lamps without adapters. Because each bulb measures roughly 2.36 inches in diameter and 4.65 inches in height, it adheres to standard A19 dimensions, allowing it to fit into most standard open shades and clamp-light reflectors. There are no wireless pairing protocols, app setups, or hub requirements involved; you simply screw the bulb into an electrical socket and switch on the fixture.

Buyers should keep a few realistic limitations in mind. The product specifications do not list dimming support, meaning these bulbs should be paired with standard on/off switches rather than wall dimmers to avoid potential flickering or operational issues. Furthermore, with no outdoor, damp, or wet-location ratings provided, these bulbs are restricted to indoor, dry-location applications. With an output of 25 micromoles per second, a single bulb is intended for modest desktop arrangements, small herb pots, or individual specimen plants rather than large-scale, high-intensity indoor crop farming.

For homeowners, renters, and hobbyists looking to sustain indoor plants without transforming their living room into a purple-tinted laboratory, the Briignite A19 LED Grow Light Bulb is a well-balanced, budget-friendly option. It combines standard E26 fixture convenience with genuine full-spectrum performance and low electricity consumption.

Each Briignite A19 LED Grow Light Bulb provides a listed 1000 lumens of brightness while drawing only 11 watts of power. In traditional incandescent terms, this light output is equivalent to a standard 100-watt bulb, giving indoor foliage ample illumination while keeping electrical usage low.

The bulb distributes this output across a wide 180-degree beam angle. This broad pattern prevents narrow light beaming and allows multiple small potted plants or an herb tray to receive consistent light coverage when placed beneath the fixture.

While many specialized grow lights produce an intense blurple glow, the Briignite LED grow light emits a balanced 4000K neutral white light to human eyes. This natural appearance blends easily into kitchens, living rooms, and bedrooms without altering your home interior aesthetic.

Beneath the 4000K white presentation, the bulb delivers a full-spectrum blend of red and blue wavelengths. This spectral balance yields a rated PPF output of 25 micromoles per second, designed to support chlorophyll absorption through vegetative growth, seed starting, and fruiting phases.

This bulb is built with a standard E26 medium screw base, ensuring direct compatibility with standard American lamp sockets, pendant drops, gooseneck desk lights, and clamp fixtures. No special ballast, external driver, or custom socket adapter is required.

With physical dimensions measuring approximately 2.36 inches in diameter and 4.65 inches in length, the bulb follows standard A19 proportions. This makes it an effortless drop-in replacement in almost any open fixture where traditional household bulbs are used.