Looks like it would be about 1400lm, based on where turbo steps down to. Convoy M21C U flashlight review | 3800 lumens, 1lumen.com
The first step is admitting that you have a problem. Haha.
I would like S2+/S3 triple Led
I believe the conventional wisdom is that Jaxman already make one (Jaxman E2L). Performance and value are a bit underwhelming though. I thought about assembling one but the need for a custom pill from a USA website scared me off.
Thank you so much for that pic! Super helpful!
Now I need a L21A and an M2
I cannot say that I feel pleased about the quality of my M21B with Osram KP CSLPM1.F1. The LED is off-center, causing a totally blurred hot spot and ugly beam, not to mention that candela/lux ratings will be significantly less than a centered LED. It looks much worse with one’s own eyes. :-(
I do not know what I am going to do with it, probably gifting it to someone to strip it for spare parts or toss it into the trash bin. I guess it is not worth bugging Simon with this since I cannot handle a soldering iron.
It's off but not too much. Have you tried the simple tricks like loosening/tightening the head/bezel? Sometimes it works. Next would be to fully remove the bezel and reflector, re-seat the center alignment piece, and slowly tighten it up with the LED lit up and see if you can hit the sweet centered spot.
Next level would be to see if anything is preventing the MCPCB from freely moving - screws or outer metal pieces might prevent it from centering properly. Screws can be good to prevent twisting, but can be bad for centering precisely.
No soldering so far 
The MCPCB screws could be tightened down a bit more on mine, and that helped the reflector sit lower and more centered.
I have the C8+ with the smaller osram emitter, I sanded the bottom of the centering ring a little to improve focus. It’s better but I could still go a little more. I think the centering rings are too thick.
They are about 2-3x too thick actually. It obviously varies by reflector and exact emitter, but for my black flat to focus optimally in my M2, it is down to 0.30mm IIRC. The WF1 it replaced needed a bit more height, maybe 0.5mm. Every reflector I’ve tried though with the 3030 centering rings and Osram flats required significant thinning of the gaskets.
Additionally, I wish centering rings would be made of black plastic and wouldn’t use a beveled inner edge. I find this often causes (sometimes severe) artifacts in reflectors. I’ve had better luck using glued down 3535 centering rings in some picky reflectors because they generally have a straight/perpendicular inner wall.
First of all, thank you for these hints. I started loosening and tightening the bezel first. It went off like a charm, wasn't even tight in the beginning. No effect at all.
I tried that next for several times, still no improvement.
That was the last thing I tried, i.e. carefully loosened the two screws to see if I can wiggle the board a bit back and forth. But in the end it didn't resolve the issue. I'm afraid it only got worse. While replacing the battery I also noticed a quite mediocre spring bypass that won't last very long. The final outcome is, more dust in the reflector (I took every precaution to keep dust from getting into the reflector, seems it was in vain) and something like a burn mark on the LED's light emitting area. Apparently, some residue from the reflector or PCB came off and burned into the phosphorus part. Well, I guess that's it then. No hard feelings, though. I'll cope with the loss of this light, especially in crazy times like these were the real problems in life are much more serious. Strangely, I felt like adopting some old nursery rhyme...
M21B, ordered on a Monday,
Shipped on a Tuesday,
Arrived on a Wednesday,
Tried out on a Thursday,
Showed flaws on Friday,
Died on a Saturday,
Buried on a Sunday,
And that was the end of M21B.
Before and after working on the centering ring...
Before removing the bezel...
After removing the bezel and trying some steps of improvement on the centering ring...
Ouch! 
With Convoys, we love the quality but the QA/QC has always been issues - many horror stories, even from resellers like RMM in the past as well.
I've done these kind of tweaks many times without these kind of problems... Oh boy, sorry...
I’ve had scares with these white flats before and burn spots on the phosphor, so far, a cotton swab with IPA and gentle twisting have removed whatever contaminate that’s been there. YMMV
Did you try sanding/filing down bottom side thickness of the centering ring?
Simon please, are the S12 and S16 flashlights same body?
I mean if it is possible to change reflectors with LEDs between these models. If it so, could you sell me one body with driver as a host and reflectors with MCPCB from both models? Thank you.
Looks to me like you had the rosin flux on the emitter in your previous picture. Obviously, it’s not your fault. It should have been cleaned with isopropil alcohol. Maybe it can still be cleaned with solvent.
Sorry ,they are different,This is the reason why I renamed it
Thank your Simon for answer.
Second question. I need to remove the stud from positive contact on M21C-U driver. Is it just soldered to the driver or any hard connection?
It’s soldered to the driver.
If you want to remove it, you need to use a heat gun,
The first picture says it has 7 amps input current and in your specifications it says „max output 4 amps“.
Any plans to improve the UI of Convoy L6? If I got it right from your specifications the current UI works like this:
„1%-10%-40%-100% (Double click side switch ----> strobe)“
I think there’s some potential here, e.g.
- offer two mode groups (ramping, stepped modes), changeable by holding the side switch and then pressing the tailswitch simultaneously
- offer „soft-off“ a.k.a. standby-mode when the tailswitch is activated
- side switch operation: click = soft on/off, hold = cycle modes/ramp up or down, doubleclick = turbo/highest ramping level
- hide strobe mode better (tripleclick)