20mm is very common but in the normal flashlight shops I haven’t really seen a 21mm.
Kaidomain has a lot of lenses but in terms of quality it’s a kind of lottery.
On the professional lens-shops you can get everything but I am unsure if it is worth the costs…
You could try to ask olight directly for a replacement, I would be very interested in their answe…
Quick update on this, I just reflowed an XML2 4C on stock copper MCPCB.
Now that light can be an everyday tool 
For anyone interested, I posted pics of the driver on the Olight S30. I’m working on getting more amps out of the stock driver. So far I’ve only increased output by 100ma or so 
The pics can be seen in the following thread:
Nooooooo I inserted my 18650 the wrong way and now my S30 won’t turn off…and have only two modes :_(
So…no reverse protection in this S30 ?
There is one in the S1…
The spring is nearly melted !
I inserted the batteyr, locked the tail, push the switch and nothing…so I immediately unscrewed the tail to see a little smoke and a smelled the burnt
It now is always on and has 2 modes : medium and high :_(
I’m really surprised that there is no reverse protection !
Yep, apparently….well that’s a good thing to know, sadly for you.
I personnaly managed to melt a S30 holster’s: the S30 switched itself on, probably with some pressure as it was inside my bag.
Silly me now uses lock out mode. :bigsmile:
It is really shocking if the s30 indeed has no reverse polarity protection! I tried to look it up but could not find a definite answer, selfbuilt mentioned nor tested it in his review, and my manual just states that the S30 does not work with battery reversed, but does not warn not to do that.
I’m starting to think the S30 isn’t exactly Olghts finest effort. Mine is away to the warranty depot right now because of an unpredictable switch. Sometimes it worked, sometimes it didn’t, and sometimes it delivered whatever mode it felt like.
They also seemed to be in an awful hurry to shovel them out the door at very deep discounts. While I’m very impressed with every other of the several Olight products I have, I’m not sure I’ll ever fully trust the S30 even if the warranty people proclaim it ‘fixed’.
I’ve got an S30R Baton II and its never given me any trouble. I swapped its cool-blue emitter for a 5C and never looked back. It lives on its little charging base on my bedside table. I don’t guess I’ve ever tested the reverse polarity protection though, but I’m willing to if you all would like. Are the rest of you talking about the last-gen light? Or the non-rechargeable one?
In the specs that are written in selfbuild's review, the S30R is mentioned to have reverse polarity protection, while it is not explicitly mentioned for the S30. That could be a coincidence....
Ah, so testing my S30R wouldn’t help anybody. Sorry. 
I’d be really surprised if it didn’t have protection since the battery goes in there “upside down”. For that matter I’d be surprised to learn that the normal S30 doesn’t have it either. I thought some form of reverse polarity protection, electrical or physical, was pretty much ubiquitous now-a-days.
Looks like Olight hired beancounter to maximize their profit…
Hmmm… It’s funny to hear of these problems with the s30. I absolutely love my s30! It is small, pretty bright stock, good UI, tail stand + a nice strong magnet, cr123 option, a better beam than similar small floody lights and yet good flood. I find the beam profile more usable than every other light I have.
I have also modded one with a 20mm Blf dd fet driver. It pulls 5A with a 30Q. Of course I added some heat management. I added a 18mm x5mm copper slug press fitted into the driver cavity, potted the driver, and added a heat path from the mcpcb to the reflector to the host. It’s VERY bright!
Anyway, the reason for my post is that I have a stock s30 driver in my parts bin. I realy like the driver and it holds some value to me but if you would realy like it we might work something out. Shipping would be the biggest hurdle!
FWIW, here some pics of the semi-fryed driver :
Right click -> open picture in new tab to zoom
You can see that the “Q2” as burnt…
So I only have medium, high and turbo available and no OFF mode at all.
Still usable, unscrew to turn off…
Are there any numbers on the q1 or q2 transistors? You may be able to replace the burnt one to get it working. I have no idea what I am talking about but it may be that q2 is stuck open allowing current to pass through when it shouldn’t be? But I don’t even know if that is a current regulator or what it is so im just blabbering:)
However if you can find the part number, you may be able to replace it?
Yeah, I think those are some transistors and the Q2 must be stuck open as you said.
Plus, I’m able to activate the strobe mode (triple click) but it only provide a regular “flicker” in the high mode, like if it can’t shut the LED off.
Anyway, all that sweet electronic is glued with a sort of resin so it may be really tricky…if you consider that my only soldering iron as a big blade (like 3mm tip)
Yes, good luck with that one;)
The resin on mine was tacky to the touch, but when I picked at it with an utility blade I was able to get it to chip away some. Idk? I would wait to see what some others say about the chip in question. If it can’t be identified idk what you could replace it with?
What did olight say? Is this something covered by warranty?
Hi,
I am from Croatia, I am new here and I have problem with my new S30. After turned on, and after few clicking it was turn of and now I can not turn on again.
I was smell like something caught fire. What you suggest?
King regards
Dalibor
Hello dalibor! Welcome to the forum.
Sorry you are having trouble with your new s30. I love the s30, it’s a great light! The smell of burning electronics is never a good smell. Unless it’s done on purpose 
if the light flickered like that, it sounds like there may have been a short somewhere in the light. Are you comfortable taking the light apart to evaluate the driver? If you smelled something burning, there should be evidence of it somewhere. That is the first thing I would do, but you may want to wait for others to offer some other diagnostics first. Or you may just want to contact Olight for a replacement?