FW3A, a TLF/BLF EDC flashlight - SST-20 available, coupon codes public

I’m brand new to this forum too. But put me in for one please!
Love the design and the idea behind it. Thanks!

Please add me to the list

Please include me, I’d like 1.

Realize I’m a few weeks behind here, but this caught my eye:

Having done mechanical design in a past career where we outsourced most production and and concept-design-production workflows with relatively simple CNC (laser cutters) as a hobbyist I feel like point 3 is a bit simplified.

There’s appreciable effort that goes into the design itself, for sure. Someone that produces their own finished product will have some experience with what’s feasible to produce and bake that into the design document.

But having a good design - a production-ready design - isn’t the same thing as having production plans.

Whenever I design a tabbed box for laser cutting, translating the design file into a work file takes appreciable time - layout for material efficiency and optimizing geometry for cutting efficiency being the key tasks.

When dealing with machining metal parts the design to work document process may well be more involved. Tool choices, speed/feed considerations far more involved than laser cutter power/feed, material selection, jigs/workholding, production sequencing (since intermediate parts may be needed between workstations/schedules), QC processes, production scheduling concerns, negotiating slight dimensional changes that could make/break the concept for your capabilities and/or the client’s needs, etc.

Suspect that the prospect for future sales of a design that’s expected to be successful beyond the initial discounted batches - and presumably without encumbrances - is the true carrot.

I’ll take one. Thanks.

With the discussion of potentially switching to the 95 CRI SST-20, I just want to double down on the LH351D.

The SST-20 is slightly higher CRI, but at 700 lm the LH351D is around 45% more efficient at the same colour temperature from what I’m seeing, and at 300 lm the LH351D is around 25% more efficient at the same colour temperature.

That’s a big difference in battery drain and heat for the same output.

edit: this is based on maukka’s tests of the SST-20 and the LH351C (my understanding is that the LH351D is slightly more efficient than the LH351D at 1000 lm, although you lose a bit of efficiency by going from 5000k to 4000k)

edit 2: actually, that’s got me thinking, after reading through the pre-production review fully, do we possibly want to look at the LH351C? If we’re expecting the light to be 900 lumens or lower (300 lumens per emitter) most of the time, then I think we’ll be sitting right in the LH351C’s target current. Yeah, we’d lose a bit of maximum lumens in turbo (all 20 seconds of it), but the better efficiency in regular use would help the light work better in regular use, and we might be able to source them more quickly.

^ with the SST-20 you loose efficiency/output but you gain a brighter hotspot (and a somewhat higher CRI). And a bit of the 25% efficiency loss is gained back because the smaller die SST-20 gives less optical losses in the TIR.

I want one LH351D 4000K 90CRI

There is indeed a lot of design/processing work done by the manufacturer and this must not be overlooked. But when working with Thorfire on the Q8 I noticed that that part is what they (as a low-end manufacturer) were already very good at. We were not able to help them with that (from the other side of the world :slight_smile: ), but that part was provided for very well. It is the what you call production plans that were lacking, they were not very creative and to my surprise they had only little idea how the actual workings are of a flashlight. By copying others Thorfire had some pretty nice models back then but not the expertise to innovate.

I’m curious how much wider the beam on the LH351C or the LH351D is than on the SST-20.

The datasheets only claim that it is 128 degrees instead of 120 degrees (although, obviously the hotspots can vary).

If it is 8 degrees wider (with relatively similar distribution within those areas), then even after accounting for the LH351C covering a larger area with its light; in the SST-20’s 120 degree beam angle, the LH351C would still produce around 17% more light with the same power (while also filling an additional 8 degrees of range, albeit without getting into the effect of the TIR).

Unless the SST-20 has a much stronger hotspot, the LH351C or the LH351D may actually be brighter in the SST-20’s light circle while also having more spill at the same power usage (albeit, not at 95 CRI).

Bare beam angle matters w/out a collimator. With - die size does. And LH351D has it over twice as large as SST-20.

Yeah, that makes sense.

I can’t find exact numbers, but if it was a doubling in central beam width from the SST-20 to the LH351D (without getting into the effect of the lens), that would triple the hotspot brightness (within the hotspot area of the SST-20), but the rest of the light would be much brighter (on average outside the range of the SST-20’s hotspot) on the LH351D.

Comparing SST-20 to LH351D, the SST-20 is quite a lot more throwy, and the LH351D is very very floody. I don’t have the exact numbers, but on Carclo’s spec sheet, there are some similar emitters to compare…

  • XP-G2: 5.5 cd/lm
  • LH351B: 3.0 cd/lm

SST-20 is similar in size to XP-G2, so ~5.5 cd/lm might be about right. However, LH351D is two steps larger than LH351B. So at a very rough guess, we’re talking ~5.5 cd/lm vs about ~2.0 cd/lm. The SST-20 likely gets more than twice as much beam intensity per lumen. Even at half the brightness, it should still throw farther… and with less light in the near field causing pupil contraction and haze, objects in the distance should be easier to see.

Looking at it from a different data source, LH351D is about as floody as XP-L HD. Probably a little bit more floody, even. And from Intl-Outdoor’s D4S specs, I see that SST-20 is about 2.6 times as throwy as XP-L HD. So I’m guessing we can expect a similar ratio in the FW3A.

So… At a very rough guess, here’s what to expect:

  • SST-20 65CRI: 15.5 kcd, 2600 lm
  • XP-L HI 75CRI: 12.5 kcd, 2800 lm
  • SST-20 95CRI: 11.5 kcd, 2000 lm
  • LH351D 70CRI: 7.5 kcd, 3300 lm
  • LH351D 90CRI: 6.5 kcd, 2800 lm


Plus or minus a pretty wide error margin.

Aside from the extra cost, and aside from people wanting high CRI, I’d kinda prefer to do a spread of XP-L HI tints instead. ~3300K, ~4100K, ~4900K, ~5700K, all in “A” or “D” tints so they’d be on the pink side of BBL. Or perhaps they can be convinced to do a Cree spread and a high-CRI emitter.

I’m not really sure what’s going on lately though. The last message I got was a bit over a week ago, and all it said was “it is fit”. I think that was about the driver shelf being cut wide enough, but I’m not sure and my request for clarification hasn’t been answered. So I guess we just wait for news as usual.

Please add me to the list. Thought I was there already, but can’t find it any more.

Add me to the list please, I’m interested in buying this flashlight!

Thats a good idea. I have a 4000k xpl-hi and even though it’s not a hcri, it’s pretty good. I would still want a warmer hcri but would jump on this as well.

We knew your username was usurped, now you are also a renegade.

Definitely! I default to XP-L Hi 4000k V2 5D in a bunch of triples and quads. The ever so slight pink looks so much better than any of the Nichia 219c that I have had and many others.

List updated in post #4. 1447 people, 2080 lights… plus ~400 on TLF.

- TK