I just ordered two of those lens/camera adapter rings from US eBay here: http://www.ebay.com/itm/320968767651.
This search shows a bunch of eBay available sources: ebay.com search for leica m39 m42 adapter.
Thanks, Tom E. Now added in op as additional source.
Why did you order this particular exemplar of the ring? Are there any differences other than the price?
I got mine finally.
The quality of my received one is better than I thought it’s definetly nice build and anodized. Lens is standard budgetlight quality. The only thing which makes me sad is the reflector, it is “foggy” tiny bits of dust are normal and if I will mod it it will get in there anyway but the whole reflector is not clear it looks like if it is steamed a bit…
Throw is still superb especially if you consider the low stock current.
The only thing I am unsure of is if I need to order new batteries because I have all my batts in pairs or if I break with my “only use similiar used batteries together rule”
For low-drain parallel applications I imagine that it does not matter (assuming that you do not break a pair to use pair+one cells in this light and then put that pair back together later for series use in another light). If you dedicate a set of somewhat similar used cells to this light and don’t also use those cells in series lights what would be the problem?
Hi tatasal, thanks for your kindly words and supporting 
Good point, hadn’t that in mind but 3 parallel cells will be even if the light pulls serious current just see a small load.
Normally I buy the batts in pairs and either I dedicate them to a light with 2 or 4 cells or I use them alternating in a single cell light. So all my pairs are kind of “matched”. If I now put one and a half pair in the courui I have to divorce one pair…
If I would buy one additional pair that wouldn’t help either, I may need to buy two additional pairs…i will ask fastech if they will sell me 3 cells…but I guess not.
I just bought from a US Seller, $1.95 ea free shipping. Ordered late last night, marked as shipped with tracking number this morning.
-Garry
Two solutions come to mind:
1) Dedicate three pairs of cells, which would then be two sets of three cells, to use with this light.
2) Since the cells are in parallel, just use two at a time, and leave the other ‘slot’ empty!
Well, that was a surprise! I ordered a second black Courui on this coupon, since a friend saw mine and had to have one. It came in the mail Wednesday last week! :bigsmile:
Ordered: Oct 23
Received: Nov 5
It only took about a week-and-a-half to get to me - pretty good! I then ordered a gray one (for my Brother-in-Law) on November 2nd. I hope it comes that quickly too! 
Ordered a black Courui on October 7th, paid for tracking, light was shipped Oct.10, tracking was refunded Oct. 21, still waiting for the light to arrive…
And the mail lady just rang the door bell and handed me the light. “Is this the package you’ve been waiting for?”
Timing, it’s all in the timing.
I think the mail lady must be reading BLF.
haha, and not the ‘other side’ !
The original link was eBay of UK - dunno how to order from there - my regular eBay account doesn't seem to work. So, searched regular eBay.com and found those other listings. I'm hoping they are all the same - seem to be. Not sure how eBay works internationally...
Finally received my Courui, after 30 days, but unfortunately with a loose reflector! No o-rings.
My gray Courui has finally landed in the USA, making a stopover for an internal ‘makeover’ by Brad, a.k.a. 18sixfifty, before making its final journey back to a country not far away from China!
Just wanted to share my new buck driver project. At this point I’ve got a stable running driver but fitting it in the courui is just to much work, I’m going to leave this one as is but not do any more, its just to much work and money to do these lights. I’ll be designing a new board for a more universal application…
This is a pic I thought would be a lot more cool than it was (its also very short range for my usual high power thrower beamshot’s, only 150yds). Also extremely hard to get this shot, I took it from a rail road bridge 60’ above the water with no solid floor.
This light is a DX courui running BU_CK with an XM-L2 U2 1A dedomed at 7.7A from NCRB’s (no higher power from ICR’s, exactly how it should be). it makes 523kCd!
All in all probably not worth the cost in this light for under 100kcd more output (using my 17dd_PIC I was getting 450kcd at 6.4A) but it was the first BU_CK I had running so it did serve its purpose.
Soldered this back to where is should be, but this is not bright as my gray one. I noticed this blinks about once in 5sec, very fast blink barely could see it. any ideas why gray medium is as bright as this black high?
Why is the second leg of the inductor hanging in mid-air?