Yup, it’s on the ‘to do’ list, thanks. Dry as a bone under there, as expected.
I’m thinking customer service will tell you that they sourced these leds by sweeping up an old flashlight factory floor. Anything that end up in the bin at the end of the day wandered it’s way into these lights 
These leds are almost always terrible bins and need to be replaced so I wouldn’t worry too much about whether it’s a gen1 or gen2.
Just get a nice XML2 on copper and swap it over, it will cost almost half the price of whole light but it’s worth it. 
used the little store points i had and got this for $7 shipped :)
For a while early on they were shipping bodies engraved with the old T6 logo, even after they started putting XM-L2 emitters in (very blue-white, as noted worth replacing anyhow).
They must have found another freight car full of the old ones somewhere, or a new cloner has started making copies of them.
Watch for the typical “new batch cheaper and worse than the last” progression — since this light has become popular, it’s likely being cloned.
I hope not all of China’s manufacturing follows this same progression.
If they do the same thing with parts for their railroads, aircraft, and power plants — especially all those new nukes — the world’s gonna have troubles.
And they’ll blame you, Old Lumens, when their country collapses. You! You made them do this to themselves ….
The tail cap threads on mine fit better than those on most of my lights. I understand that the precision of numerical control machining is mainly limited by thermal expansion, so it gets worse as the process is sped up.
This light was already heavily cloned. (eg what we are discussing here was never the original)
This doesn’t mean that cheaper clones can’t be made but generally the process seems to bottom out. (like with the SRK) I think the F13 lights probably bottomed out a while ago.
I wrapped duct tape, textile, around the thread, it works, it is smooth and accurate.
Get some good silicon gel lubricant and put it on the threads and o-ring…goes a long way in making it smooth screwing it in
I use duct tape on my two Yezl t9s, because they have intermittent tail switches for electronic switch drivers, but now have regular drivers. The threads are anodized but not completely. It works nicely but eventually starts getting loose. Aluminum foil epoxied on lasts longer. I have some thin copper but haven’t tried it yet. I have a couple of very cheap SK-68s that I have junked because of the tail threads.
Thanks O.L., ordered one for my DST build.Hopefully, the threads are good and don’t wobble too much.
DST? (I’m only familiar with that in the context of the Defiant Super Thrower.)
Yes sir, digging through old threads shows the battery tube fits the Defiant.Now I need a crazy driver for it!
Ermahgerd!!!
Click for full size
It fits!!!
And a straight up Li Ion in lieu of those 1.5vdc alkalines is CRAZY bright!
This is an ultrafire c 308 battery tube that fits but just looks stupid.I am pretty pumped to get this now and finally finish what I started.This light in shorty mode is awesome, now to search out 5+ amp driver.Thanks for confirming the fit Warhawk!
Thanks guys for all the answers regarding the tail cap fit. It seems there are a few people with loose tail cap threads but for $9 you complain too much! By the way mine has been lubed with silicon grease and it is BY FAR the loosest fitting tail cap out of over 100 lights I own. Anyway I have ordered another and hopefully this one is better.
Does it work in the other direction? (F13 head w/ DST tube)
While we’re on the subject… can you point me to a discussion where different tubes which fit the DST are mentioned?
> won’t quite lock out by unscrewing the tail cap after some wear,
> because some aluminum shows through the anodizing
Cautionary. Do you think a wrap with teflon tape would work, or would it eat up the tape?
I guess the threads aren’t particularly smooth since they ate up the anodizing.
Indeed it does! but i like it!
Well crap, looks like I need to order another one for my DST!