yeah, that caught my attention too.
I cant find any information regarding this LED, but Lumintop assured me that theres no typo and that it is really the name of this LED and not XM-L2 T6 3C :D!
But Cree doesn’t make an XM-L2 U2 3C :~
Yeah, but Lumintop said that they are sure its what they call it :D!
lol! lumintop needs to take some pics of the bin code! 
Little update - it was rather foggy+camera didnt perform up to the task so beamshots will be delayed for a week.
I will try, however, to finalise my review in coming days in order not to postpone it for too long ;)!
Thanks for understanding to those, who are interesting in this review and I will keep you all updated :)!
What is the ID of the Body tube??
That 4AA holder with Eneloops in it, measures at 35.5mm in Diameter and 35.6mm would be better, for clearance.
I've got one of these coming and if it will hold a 4AA holder, I could see it with an MT-G2 and 2s/2p 14500s DD.
I bought some of these some time ago. In my amateur opinion, they seem like they really are 3C. Haven't tried to test output to see if not T6, but I trust the vendor. There is also a picture of the Cree label there.
Looking forward to the full review veer 
EDIT: I'm a ditz. I missed the 2 in XML2. I haven't heard of this emitter either.
On their website (http://www.lumintop.com/Products_45.html#.UkCcRxvD_mE) they are saying XM-L2 T6, so probably that's what it is because I don't see how a 3C tint exists in the U2 bin either - don't think the Lumintop source there knows, maybe... If it did exist, everyone would be jumping all over it - no sacrificing output for a neutral tint, how it should be.
Interesting ImA4Wheelr - that CREE label does look legit from the Convoy guy - think Simon?? If they did it for XML's, maybe a batch was released for XM-L2's, but strange we are not hearing of it anywhere else...
My digital caliper shows </=34.88mm.
Im still waiting for my 4xAA adapter from FT, so cant confirm whether it will ever fit or not.
I have 4xAA adapter from FT, and it tight fit.
The holder itself should fit, but not with batteries. If you find some undersized NiMHs (smaller OD), it might work, but probably not.
Finally updated review, its done now, see original post :D!
If I wanted one of these in the 3C, I presume Lumintop is the only place to order them from? And I don’t see an actual order form. so I guess I need to fill out the order online and have someone contact me?
XM-L2 U2 3C is not a warm white tint, but a neutral white tint. XM-L1 U2 3C is not brighter than XM-L2 T6 3C.
Then if "much warmer than that of D40A NW or EA8W!" that is not a neutral 3C tint but really a warm white tint which can't be 3C.
Not to mention about the bold claim on the U2 bin for "3C" or "warm white".
Looks like you will have to contact their rep through Skype and ask for a quote 
Im not a tint/CREE bin pro, but I do find it odd that there is no information regarding this LED and yet, Lumintop were insisting that its correct naming of that LED, I specifically asked them about it when I couldnt find any iformation regarding it online :D!
So far loving this light, its best with lithiums and Im now pro-lithium batteries dude, just buy the best batteries, decent charger and decent battery testers/DMM and youll be safe :D!
I would like to try to build a maglite 1D mod with a driver that can do H/M/L and support Alkaline D’s, AA’s, and the lithium batteries the SD10 supports.
Nice review!
But I’d say the only thing we know for sure about that emitter going by your comparison photos is that it’s ~5000k NW and that it’s an XM-L2. The output bin specification they give sounds unlikely and the warm white moniker is confusing. Do you have any lights with known emitter tints, i.e LEDs you bought and installed yourself to compare against?
That’s the best way to get a ballpark on what emitter is actually installed in your light. Small variations in tint/temperature can be quite obvious to the eye when compared side by side, even when comparing emitters from different parts of the same tint classification/bin/quadrangle/thingy.
I expect we will be seeing XM-L2 NW U2 emitters from cree at some point. They’re probably already occurring in smaller quantities mixed into the mass order minimum T6 order codes but just not available in high enough quantity for Cree to justify sorting them out specifically and selling them as single bin reels.
As usual I’m just speculating on all this bin stuff, if only we had a Cree insider on the forum who could give us a better insight into the fascinating world of binning and emitter production 
I havent made any tint modifications to my lights, yet ( ) so I cant comment regarding possible similarities etc :D!
Ill bump this up since its now in correct subforum, for those who might have missed it :D!
Thanks, Admin, for moving this one ;)!