Yep 10% or better seems about right. I de-lensed 2 of them… FT03 and a TM36 seen gains in both out put and throw… but was told I was full of it by a couple German Experts.
But then I never really gave a shit what the experts say or think, I do this for fun… 
Experts have fun too 
From what is measured before, glass and quartz lenses of flashlights, 10% loss from adding a non-AR coated window sounds a bit much, 5% is more what I would expect. But this situation is a bit different from a flashlight lens, so maybe a special window that needs to endure fast temperature changes is less transparent? Anyway, it is what it is. 
Vinh claims it gives +5%.
I'm working on a before/after now with my 1504 pill. I got the before #'s, working on the cut but it's a difficult one. Need a better, sharper blade. Will get back to it tonight, hopefully.
The higher lumens ouptut indicates, that the lens probably doesn't touch the phosphor. This is different from de-doming.
djozz Thank you very much for your efforts, again please don’t stop 
, we should pay you for this
Correct it dose not. Now factor in the tolerances, emitting area to top of glass has a larger tolerance then the Datum B to top of glass has? So it’s the phosphorous pad that varies also.
Is Neal still the best place to get the SBT90.2? I blew my BLF GT90 LED.... added the wrong battery carriers (of the original BLF GT). When I noticed the mistake it was too late.
Neal still has them listed, dunno if he really has them. I ordered one Friday, and he's trying to text me - not sure if it's about the LED, something else in the order, or unrelated. Conversation is like this:
Neal -> hello tom
12 hrs later:
Tom -> Hi!
...
That was my response 2 hrs ago - it's probably like 4 AM there now... :FACEPALM:
If he has them, I'll have to order one.
Neal has them in stock, just ordered 1
what MCPCB does this LED need from Kaidoman?.
looking for the best one.
for s21a host.
thanks.
kind thanks
I have one from intl-outdoor on a 32mm noctigon. SB flux bin vs the SA bin nealsgadgets has listed. I’m not sure of the color bin and am still waiting for the 4x18a that will be its home.
A UB flux bin J3 color bin would be awesome! 3955 to 4230 lm at 9A and tint at or below 5700k and near or below the bbl.
I wanted to use the driver from fw21a and put it in a convoy s21a but I don’t think that will work because I would need an electronic switch.
With that being said would anyone be able to help me find a high amp 22mm driver to use in a M26C to power the sbt90.2
Edit: M26C
A FET DD driver is pretty much your only option to get the ~20A for the SBT90.2. Mtnelectronics has the drivers and kaidomain has this one.
Great. I actually have a couple of those that I ordered by mistake for a different build.
Thanks
Kawiboy, What does that black ring that sort of looks like felt in the picture around the base of the SBT90.2 do for you? Remove beam artifacts or insulate the reflector? Curious. Awesome builds. Thanks
That is the old SBT90 centering ring which is a 10mmx10mm opening I had to make it 10mmx11mm for the SBT90.2…