Osram have a few different emitters that they use in flashlights, mainly for high throw. People refer to them in different ways, normally as White Flat. This post aims to clear up the naming and also help me remember which one is which.

Bits of the information are based on this long thread on BLF, especially Tom E’s post here, as well as looking through Osram’s site, Intl-Outdoor, SkyLumen and Manker.

These are the emitters:

  • KW CULNM1.TG Boost HL
  • KW CULPM1.TG Boost HX

S or U package size

The S or U refers to the package size. S is 3030 (3mm square). U is 4040 (4mm square). Some reviewers have shown that the bigger U ones can take a bit more current than the S, so can be brighter and throw further. I remember this as “S for small”.

N or P emitter size

The N or P refers to the emitter size (the yellow bit). N is 1mm square and P is 2mm square. The bigger P emitter means there’s more lumens but they’re spread out, so it’s lower intensity. I remember this as “N for narrow”.


The TG at the end refers to white LEDs. Osram have other colours available too:

  • .TG white
  • .F1 green (highest intensity)
  • .23 red
  • .FY yellow
  • .14 blue

Common names

The S ones (small 3030 package) are commonly referred to as W1 and W2. Everyone seems to agree about this.

The newer U ones (4040 package) are referred to in different ways:

  • Officially the 1mm (N) is the Boost HL and the 2mm (P) is the Boost HX (X for eXtra powerful?)
  • Vihn from Skylumen calls these the W1.1 and W2.1, so the same as W1 and W2 but with .1 on the end for the bigger package
  • Hank from Intl-Outdoor (Emisar/Noctigon) calls these the W2.1 and W2.2


S (3030)U (4040)
N (1mm2)CSLNM1 / W1CULNM1 / Boost HL
P (2mm2)CSLPM1 / W2CULPM1 / Boost HX

Flashlights with the Osram emitters

Here’s some of my flashlights with different emitters.

GT Nano (W1) left and Convoy S21B (Boost HX) right

W1 Flashlights

The Acebeam E10 and L17 also come with a W1.

W2 Flashlights

  • Convoy Z1

The Noctigon KR1 and K1 and Acebeam L18 and L19 also come with a W2.

Boost HL Flashlights

I don’t have any lights with the Boost HL. The Manker MC13 and Lumintop X1L come with these. The Noctigon KR1 and K1 are available with this LED as an option too.

Boost HX Flashlights

  • Convoy S21B

The Convoy L21A and Olight Marauder 2 also come with a Boost HX LED. The Noctigon KR1 and K1 are available with this LED as an option too.

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