USEFUL TERMS:

• Emitter: The component that produces light (Light-Emitting Diode in this case)
• Die: The actual light-emitting portion of an LED
• Phosphor: The yellowish layer seen on white emitters, this is layered on top of a blue LED and produces yellow/orange light, mixing and allowing for a true white LED.
  • LES: Light-Emitting Surface, area (in mm^(2)) that actually shines to produce light. Smaller LES = more intensity per lumen.
• Thermal Pad: Small metal pads underneath the LED that dissipate heat, and act as electrical leads
• Dome: A silicone domelike lens on top of the die that increases output and produces a flooder beam
• Vf: Forward voltage, the voltage at which an LED is designed to operate (usually 3v, 6v or 12v)
• Package: The total size of the LED chip (in millimeters x millimeters)
  • Footprint: For soldering purposes, the size/shape of the electrical pads underneath the LED, expressed as mm*mm (for example, a 5050 emitter is 5.0mm by 5.0mm) - this list is organized by LED footprint
• MCPCB: Copper or aluminum circuit board that allows the LED to be wired to the driver, and provides heatsinking
  • DTP: Direct Thermal Path, an LED + PCB construction that allows for heat to be directly drawn from LED into host. Important for high-power flashlights
• Luminous Efficacy: The amount of light (Lumens) produced at a certain power level (Watts)
• CRI: Color-Rendering Index, or (basically) how well colors are rendered by a light source.
  • Ra: Average of the rendered colors R1-R8 (specific industry-standard shades) - Interchangeable with CRI (ex: 80 CRI = Ra80). Each individual value is measured on a scale of 0-100, as is the total average.
  • R9xxx: A specific shade of red used to calculate total Extended CRI (Re instead of Ra). LEDs have a difficult time rendering reds, so this specific value in very important when discussing total color-rendering capability. R9050 is good, R9080 is great.
• Temperature (CCT): Color-Correlated Temperature - how "warm" or "cool" the LED is, refers to the ratio of red to blue light in a white light source, measured in Kelvin (K)
• Tint (Delta-UV, Δuv or duv): the ration of green to magenta in a white light source (negative is more magenta, positive is more green)
• Monochromatic: Light emitted within a single wavelength (color) of the electromagnetic spectrum, rather than having multiple wavelengths
• Broadband/Narrowband: In this case, when referring to colored LEDs that aren't monochromatic - basically they produce a slightly wider range of colors
• LEP: Laser-excited Phosphor - white light produced by phosphor excited by a blue or UV laser, rather than a traditional LED. Very intense beam produced as a result.

MANUFACTURERS

Cree: American brand, manufacturing done in China. Long-time most popular brand for flashlights, and the benchmark against which others are usually compared. Usually aims for decent color and high output. Their emitters do tend to have green tints, some more than others. Popular emitters from Cree include the XP-L HD and XP-L HI, XP-L2, XM-L2, XHP35(HD/HI), XHP50(.2), and XHP70(.2). Technically named Wolfspeed Inc, Cree is the LED division of the company.

Nichia: Japanese brand, and the biggest LED brand. Makes lower powered high CRI emitters. Most popular for the 219b series, loved for their absolutely beautiful tint and compatibility with XP footprints. Their 219Cs were popular for a little while before the rise of Samsung's LH351 series, and later the 519A that offers excellent blend of output and color. Other Nichia emitters that enthusiasts use include the E21A, 144A, and Optisolis series.

Samsung: South Korean conglomerate that makes everything tech related, including LEDs. Pretty much the only Samsung emitters we use are in their LH351 series, particularly the LH351D. Depending on the bin the tint can be a bit green, but they're high CRI and just as high output as a Cree XP-L, and also compatible with an XP footprint.

Luminus: Chinese owned (originally based in California), manufactures LEDs in China. In recent years they have produced many emitters popular for flashlights, with both high-CRI and high-power options. Many of their emitters are known to be very green in tint. The SST-20 is an XP footprint emitter that throws even further than the XP-L HI and is available in high CRI. The SFT40 is a small but powerful LED that produces a throwy beam, while the SBT90.2 is large, extremely bright and throwy. Very common is the SST-40, which is pretty much a brighter XM-L2.

Osram: Osram is a German lighting manufacturer. We mostly only use one family of emitters manufactured by Osram. Their Oslon series has a few emitters with long complicated names and very small dies. These LEDs are capable of high outputs, and their small emitting area makes these emitters ideal in compact throwers. The Osconiq LEDs are used in a few lights as well.

Getian: Chinese manufacturer, relatively new in the world of flashlights. Their GT-FC40 LED has become very popular for being a high-CRI alternative to the XHP70. More LEDs may make their way into flashlights - in particular, look out for FC15, FC30 and FC60.

San'an Optoelectronics: Another Chinese manufacturer, new to the flashlight world with their extremely high-power SFS, SFN, and SFQ LEDs. The SFN55 in particular is capable of 10,000+ lumens. These are starting to become popular in lights that go for maximum possible output, though they are known to have poor greenish tint and low-CRI.

Philips Lumileds: The massive Dutch company Philips created Lumileds, known for their LUXEON line. No longer popular in enthusiast lights, but occasionally still found in lights from brands like Olight, Fenix, and Streamlight to name a few. They do produce high-power, high-CRI LEDs, but these aren't seen in flashlights.

LatticePower: Pioneer and leader in Gallium-Nitride (GaN) on Silicon LED technology, based in China. Pretty rare in the world of flashlights but more emitters are appearing in popular models.

CREE:

3535 emitters:

• XP-L HD: Domed, pretty typical when it comes to output, about 1200 lumens max. Very common. Largely superseded by LH351D
• XP-L2: Domed, more phosphor area than the XP-L. A bit higher output, but worse tint. Not popular
• XP-L HI: An XP-L without a dome. More throw, less tint shift. Still bright at 1200 lumens, great natural tint with CRI 80+ versions available in warm temps. Very popular, recently updated with flipchip version that has slightly better performance
• XP-G2: Smaller dome than XP-L, and smaller die. Less output too. Good for tiny multi-emitter lights.
• XP-G3: Largerized XP-G, more phosphor, more lumens, worse tint. These are gross, nobody likes them.
• XP-E2: Update to now-obsolete XR-E, the XP-E is notable for its many different unique colored variants. White version is unremarkable and uncompetitive; we only care about the colors
• XHP35 (12v): Capable of high outputs. Available in a domed high-output (HD) or domeless high-intensity (HI) version. HI version is popular for its great tint and decently high CRI (often 80+), makes for an excellent warm thrower LED in 4000K. Recently discontinued but still veery in-demand
• XHP35.2 HI: Update that offers higher output/efficiency and rosier tint at the expense of some CRI.

5050 emitters:

• XM-L2 (3V): Similar to the XP-L, but in a slightly bigger form factor. Once extremely common for great balance of performance, decent color and cost. Recently updated by Cree, newer versions are extremely efficient and even brighter than before. Now mostly superseded by Luminus SST40 - however these may make a comeback with the new updates
• XHP50.2 (6v or 12v): A quad-die emitter. 6V or 12V depending on how you wire it. Fairly small but efficient and very bright and floody, up to 4,500 lumens. More phosphor, more light, worse tint than the previous generation. Lookout for the upcoming XHP50.3 HD that should be available in lights soon
• XHP50.3 HI (3v, 6v or 12v): A more efficient and domeless version of the XHP50 design, maintains very high output but with double the intensity. Supposedly available in warm white and 90+ CRI versions, should have better color than the domed version of the LED.

7070 (6v or 12v):

• XHP70.X: Large, super floody domed quad-die LED which is very efficient and capable of extremely high outputs (easily 4,000+ and up to 9,000 when pushed hard enough). Available in nice warm color temps, and 90+ CRI versions are available in exchange for less performance. Tint is fairly neutral, though these are notorious for dramatic color shifts in the beam, with warm greenish hotspots and cool rosy spill. Most common is the XHP70.2, offering better performance is the newer XHP70.3 HD
• XHP70.3 HI: Double the intensity of the domed version, likely with better tint. Very high output and warm white, 90+ CRI versions exist.

NICHIA

Tiny emitters (3v):

• E21A: This is a 2121 emitter with no dome, just straight phosphor. Better beam than a 219C, but not super bright. Extremely high-CRI, R9080, and neutral tint that mimics sunlight. E21A quads are now largely superseded by B35A lights
• E17A: Like the E21A, but 1717. Both of these emitters are available in a wide range of colors, from 1850K - 6500K, and E17a has some fun colors like Azure.

3535 (3v):

• 219B: Everyone's favorite. Not built for output, but they made really beautiful beams and available in high CRI, R9080. Known to have a very 'rosy' tint (negative duv), especially the SW45k bin. Small dome gives a balanced beam. These will mostly be superseded by 519a, though they are still considered the king of tint
• 219C: The successor to the 219B. Brighter, but the tint isn't as good. Also available in high CRI. Largely superseded by Luminus SST20 and Samsung LH351D, which are brighter and high-CRI
• 219F: Basically another successor to 219C, not meaningfully different other than option for bins with R9080. Does not like being overdriven. Biggest point of interest is the super-warm 1800K version that is meant to replace sodium-vapor produced light.
• 519A: Very bright, R9080, pleasant neutral or rosy tint, and available in a wide range of color temps. Large dome and very floody, comparable to LH351D. Common footprint makes them easy to swap into other lights, and they are easily dedomed for more intensity and warmer + rosier tint. Everybody's new favorite LED, seen everywhere and for good reason. Recently replaced with mildly superior 519a-V1

3535 (6v):

• 719A: Flat emitter with two dies stacked on top of each other. Similar color to domeless 519a, higher output, slightly floodier due to larger die. Brighter but lower-CRI (R9050) than B35AM. Will potentially replace the XHP35HI in many lights going forward

3.65x3.65 (6v):

• B35AM: Four E21A dies, this is the brightest (~1300 lumens depending on CCT) and throwiest ultra-high CRI (R9080) emitter available. Very natural, sunlight-like tint. Footprint is a bit unconventional, being 3.65mm x 3.65mm, so it requires a unique MCPCB (no DTP available, limiting max output)

5050 (6v):

• 144A: The 144A is Nichia's answer to Cree's XHP50. Different footprint though. Also no thermal pad, so they never really caught on. High-CRI but has strong tint-shift when used without diffusion. Armytek provides the Wizard C2 Pro with this emitter.

SAMSUNG

3535 (3v)

• LH351D: Common XP footprint. Big die, large dome, very floody, high CRI, bright - excellent all-round LED. These beat out the XP-L2 when it comes to output. They tend to be about as green as 219C, if not a bit more. This varies from bin to bin but tends to be inconsistent. One of the few LEDs available in high-CRI cool white variants. Good but superseded by Nichia 519a which performs similarly, still nice inexpensive option

LUMINUS

3535 (3v):

• SST-20: Domed, small die. Cousin to Cree's XP-G2, much throwier (more so than XP-L HI) and available in high CRI and many color temperatures. Low-CRI version is very bright and throws far, while the dimmer 95+ CRI version (4000K and below) is R9080. Known for weird yellowish-greenish tint, tends to be green at low currents, but bins are available with neutral or even negative duv. Very popular for its combination of performance, throw, color, and low price. Also available in a deep red version.

5050 (3v):

• SST-40: Cousin to the XM-L2. Perfectly capable of being overdriven, up to about 9A. Easily capable of 2000+ lumens.
• SFT40: Essentially a domeless SST40, capable of 2000+ lumens while being very throwy. Great balanced thrower and performer, but very cool (6500K), a bit green, and low-CRI.

5050 (6v or 12v):

• SST70: Powerful domed LED, larger than SST40. Competes with XHP50.2, slightly throwier. Capable of ~4,500 lumens when driven hard. Very green at lower power.
• SFT70: Domeless, very throwy version of SST70. May be a strong SBT90.2 competitor at a higher forward voltage, less max output.

11x10mm (3v):

• SBT90.2: Large and extremely power-hungry LED that can produce 5000+ lumens and is very throwy. Efficient but greenish at lower powers, this is an excellent high-performance LED - but comes at a steep cost.

OSRAM

3030 emitters (3v):

• KW CSLNM1.TG (White Flat): AKA W1 - 1mm^(2) emitting area. One of the best choices if you want compact throw.
• KW CSLPM1.TG: AKA W2 - 2mm^(2) emitting area. Less throwy but brighter than the 1mm version, it can be pushed very hard for extremely high output when used in multi-emitter lights. Only available in 5700K, low-CRI version with nice neutral tint.

3737 (3v):

• GW PUSTA1.PM: "Duris" series of LEDs, known as the P9 (Osram loves to make things hard apparently) - Smallish domed emitter with decently high output. Available in a range of CCTs, only really seen in cool white. Poor coloration, strong tint-shift. Brighter successor to the P8 (GW PUSRA1.PM), competes with XP-L HD with slightly better efficiency.

4040 emitters (3v):

• KW CULNM1.TG (Boost HL): Also 1mm^(2) emitting area, same as the 3030 version. Slightly brighter though, due to larger thermal pad that can sink more heat. Sometimes called W2.1
• KW CULPM1.TG (Boost HX): Same 2mm^(2) die as the 3030 version. Also slightly higher max output due to larger thermal pad. Sometimes called W2.2

The above emitters are also available in colored Red, Yellow/Amber, Green, and Blue versions.

View this page for more clarification on Oslon naming schemes, as flashlight manufacturers and hobbyists use a variety of names.

GETIAN

• GT-FC40: 7070, 12V. A large domeless LED with 16 dies, the FC40 is very high-CRI (95+, R9080) that produces 4000+ lumens when driven hard, and is relatively throwy compared to domed XHP70. Available in a range of color temps including a super-warm 1800K. Looks like a waffle. Was popular but now mostly outcompeted by XHP70.3 HI

SAN'AN

These emitters are fairly new to flashlights, and while pretty popular, I still do not know much about them. The naming schemes are confusing. These LEDs seem capable of incredibly high outputs when pushed very hard, especially notable at these low voltages, but these numbers may not be realistic in actual flashlights. Still, expect them to be very popular for powerhouse and hotrod flashlights.

3535 (3v):

• SFS80: Comparable size to XP-L HI or CSLPM1, but much higher output; very bright (almost 2,000 lumens when pushed very hard), available in a 4000K 85 CRI version.
• SFQ43: Supposedly even brighter, appears to be the successor to the above LED. Very green tint.

5050 (3v):

• SFQ60: Very bright, about 3,000 lumens. Competes with Cree XHP50, but lower Vf.

11x10mm (3v):

• SFH55: Huge domeless LED with 16 dies, capable of well over 10,000 lumens when pushed hard enough. Cool white and greenish. Large flat surface is somewhat floody. Easily swapped with SBT90.2, brighter but less throw
• SFN55.2: Smaller 9-die surface, about the size of the Cree XHP70.2. Small and flat surface means it's pretty throwy, and is extremely bright at ~8,000 lumens. Combination of size and output places it between the XHP70.2 and the SBT90.2. Available in a range of CCTs and CRI, large color variation depending on power level, generally quite greenish.
• SFN60: Supposedly even brighter than SFN55.2, apparently the successor. 6500K version has decent tint, and slightly green tint in 5500K version, but available in 3000K, high-CRI variant.

11x11mm (3v):

• SFP55: Massive 25-die surface, claiming 22,000 lumens from a single 3v LED! No detailed testing yet (most I've seen in a light is 13k lumens, still very impressive). Very cool white but decent tint.

LUMILEDS

3535 (3v):

• LUXEON V2: It exists. Brighter than competing XP-G2/3, 70CRI and cool white.

3737 (3v)

• LUXEON TX: High-efficiency small emitter, lower Vf than XP-G. Available in warm white, high-CRI variants, has decent tint but a strong blue spike. Used in many small Olights (i3E - i3T)

4040 (3v):

• LUXEON V: It also exists, I don't think anyone cares about it though. 70 CRI, cool or neutral white, very bright ~2,400 lumens. Can take being overdriven without lasting damage. Somewhat better efficiency than SST40. Probably no reason to think about this one when the new XM-L2 exists

LATTICEPOWER

2323 (3v)

• CSP2323: The Chip-Scale Packaging emitter used in the Wurkkos TS10. Small, about the size of E21A, but brighter and very slightly worse color rendering.

7070 (6v):

• P70: Large flat LED that is throwy and very bright, comparable to domeless XHP70. About 6500K, up to 4k lumens when pushed hard. Used in Acebeam L35.

MISCELLANEOUS LEDS

5050

• YinDing "Round LED" (3v) - a flat LED with a circular (rather than square) die, very bright and impressive throw that competes with Osram throwers. Round die allows for nice beam pattern, but terrible low-CRI greenish color. Available in a 3000K variant. Nice beam due to round die, but poor efficiency and low max current compared to XHP35 HI and XP-L HI
• LeiTang 5050 round - Another round die emitter, with a unique silica protector over the die. Greenish and ugly, good efficiency. Used in some Olight throwers.
• Rayten 5050 Round LED - Yet another similar flat emitter with round die. It exists and everybody talks about it but I've never seen it actually tested or used.

5mm

• Yuji 5mm LED - Classic 5mm through-hole LED design. High-CRI, available in a variety of color temps.

FUTURE LEDS

Emitters that have gotten a lot of talk, but either aren't available or haven't been used in lights yet.

3030

• Getian GTFC30 (6v/12v) - Flat quad-die emitter very similar to XHP50 HI, available in high-efficiency or R9080 variants.
• CREE XP-G4 (3v) - Another version with even higher output, supposedly better color this time around.

3535

• Nichia 719a (6v) - Double-stacked die, high-CRI (R9050) thrower LED, comparable to XHP35 HI but less bright.
• Nichia 519a-V1 (3v) - Slightly updated version of 519a, lower Vf and less control over flux bins, no 4500K version. Technically 219b is also the V1 version, in both cases the original is discontinued so this distinction won't matter soon.
• Nichia 219c-V2 - Factory domeless 219c that offers high-CRI throw in a common package.
• Luminus SFT20 - Domeless SST20, high-CRI very intense thrower.
• CREE XP-P - Flat emitter with very small 1mm^(2) LES, up to 700 lumens in high-CRI. May be the high-CRI Osram killer we've been waiting for... depending on how competition with the above shakes out.

5050

• Getian GT-FC60 (6v/12v) - 16-die emitter larger than XHP70, offering R9080 variants. Higher efficiency dies than FC40.
• Rayten 5050 Quad (3v) - A custom emitter ordered for enthusiasts, hasn't materialized yet. High-CRI R9070, ~4500K thrower with quad dies in a low-voltage design, should offer great throw as an alternative to the SFT40.
• CREE XM-L2 Flipchip (3v) - An updated version that offers superior performance, slightly different coloration as a result.

If I've missed anything or made any mistakes, please let me know below! I will also be working on a list of less common/popular emitters, and I have a spreadsheet with a list of actual specs and links to tests and specsheets.