Sorry Sharpthangs, I missed your question somehow. There are 2 o-rings actually, along with a healthy amount of lube:
I was supposed to stop buying flashlights for a while (after my recent Sky Ray King purchase), but flasholism doesn’t always go according to plan (or it does, depending on how you look at it, heh). Also ordered the host kit from CNQG , as well as this one from verosale.com . It appears to be the same basic host (only an XR-E Q5 though, and almost certainly not HAIII) in an interesting colour.
Yea that last one looks the same but I see no tailcap magnet or HAIII so its only appearances.
Too bad because I would much prefer a XR-E Q5 in it rather than a XML!
imho XML zoom aren’t good light.
In flood position it’s ok, you got a big amount of light. No artefacts or imperfection.
In the tele position you get a VERY BIG and not so bright LED image and you lose much of your lumen due to the difficulty to concentrate te very flood beam of XML.
Zoom light works better with XP-E or XP-G.
This torch needs a XP-G2 driven at 2A 
this host sold at fasttech looks to be the same as the ones mentioned in this thread…
http://www.fasttech.com/products/1618/10002463/1576102
for anyone that owns this, i have a question… could somebody measure the size of the pill threads? sorry for the bump ><