What’s the difference between the s21a and S21b?
Based on the pictures, the S21A is like the S2+, whereas the S21B is like the S11.
Other than that, they seem to have the same UI options and similar emitter options. (The S21B does have some OSRAM variants though.)
The S21A also has an OP reflector while the S21B has a smooth one, but that might be customizable if you placed the order with Simon.
So the difference is just the host shape? They both use the same battery, and I guess either can use any of the choices of emitter and reflector that Simon offers.
Just trying to clarify.
Would be nice if someone could come up with a chart for all the different convoy hosts and what their names mean 
I tried that a while ago. It was…… painful.
Generally, I think Simon meant S, M, and L names to represent small, medium, and large. The numbers in the early days used to be random/sequential according to their design and/or release date. Now, it appears the numbers refer to battery configuration mostly and suffix letters are now the version indicator based on time of design/release. It’s confusing when legacy names / models are still popular (S2+, M2, L6 etc.).
For example, the M21 series are all “medium” sized lights, and use a 21700. The “A” was released first, and there are B and C variants that came after. Unfortunately for those trying to associate the name to a design, they are not in order of size. Small to large goes B to A to C.
S21B accepts 22mm driver and its PCB base is integrated shelf instead of pill, while S21A accepts 20mm driver and uses pill.
Yeah I’ve been able to figure it out mostly based on the photos and random forum posts. In some of the previous models in his Shop he even writes it in the picture/listing (for e.g. M21A - C8+ 21700 version). Would be convenient if that were done on all the relevant models but is probably a lot of work.
Awesome! That helps a lot - thanks 
I am producing a lighted switch with a diameter of 20mm
Someone tried to put the 21700 battery in the Convoy S11? It works? Will the positive terminal of the battery not deform?
It’s generally not worth lighting the stainless switches. it requires so much current to even be visible that it’s just a battery drain IMO.
excellent ! I’ll order one as soon as it is available :partying_face:
I tried with Samsung 50E and 40T - both work fine. Although I’ve put things together by myself but I assume stock version will take 21700 as well. Some “protected” 18650 are 5-7 mm longer so most of producers take it into account. Just pay attention your 21700 is 70mm long, not more. Which means it must be unprotected which (IMHO) is better. But I would recommend to use it with the adapter. S11 can take 26650 which means 21700 may rattle inside. The difference between 26650 and 21700 is 5mm, while between 21700 and 18650 is 3mm. When you bump your flashlight - this may make a difference.
Does anyone have beamshots of the lh351d 3500k or 2700k?
I would be interested to see these as well.
To everyone owns M21C-U, does your light after switching on high in 4mode setting step down from HIgH to moonlight within 10seconds?
Caramba just asked me about it if i have this problem he is experiancing and i just checked mine and it does this within 10s when set to MAX.
Weird...
Yes, I noticed this on my M21C-U for 4 mode. This happened on high mode turn off(memory) and turn on again. It also happened for from off, double click to high.
I did some testing. This happened when battery is 3.8 volt and below. With a fresh battery, everything is fine.
I’m using P42A and 40T for M21C-U.
My combo exactly.
It shouldn’t step down from 100% to 0.1% at 3.8V
I’ve got an lh351d in 2700k coming in the post, I’ll post pictures when it arrives
I’ve just tested mine (with the xhp70.2) and it doesn’t do that, maybe the cell in yours isn’t providing the required voltage for that current.
Protected cell?