hi guys, can anyone explain what is the difference? i already have the T6 built into convoy s2 host, but today they have U2 with everything else same? is it just me or…?
You have XM-L or XM-L2?
The difference between a T6 and U2 is pretty much invisible to the naked eye except between very specific A/B comparisons. But this is made even harder to spot because the U2 is a cooler temp LED which to the eye will appear brighter.
I wouldn’t worry too much but I will say getting led’s on the tail end of the production run is usually a better bet when it comes to tint variability, as in you’ll actually get the tint they’re specified to. Newer led’s when bought from budget places will tend to be green. I hate green led’s I’d much rather see almost any other color but green.
Explain what ? Its supposed to be the same tint (4C) but with brighter flux bin (U2>T6), meaning you get a little more light from the same tint.
If its real it is a very good news and render the T6 4C obsolete !
No, the U2 is not cooler, its the brightness bin not the tint. Before, the U2 was only cool white because its easier to get more lumens with CW. But its possible that they now make neutral white U2 LED, they did the same thing with the first gen XM-L.
i have the very same from the picture XM L2 T6 4C ordered from fasttech few months ago and now i wonder if there is going to be a visible difference…
so you are saying that right now the older T6 xml2 is better buy…
If it’s the same tint bin I don’t see why it would be rated as having a tint range 100k narrower and on the cooler end of the spectrum AND have the same rated lumen output. With these Chinese dealers you simply can not trust the specs they put out. But experience has told me if you value tint more than absolute lumen output then you would be better off buying the T6 nearer the tail end of the production when the newer brightness came out.
My first gen XP-G’s, XM-L’s, and way back when XR-E’s were barely going from Q5 to R2’s, every new generation in Chinese budget lights had horrible tints whenever you got the latest and greatest brightness bin regardless of the “rated” tint.
Somethin fishy in Mao Tse-tung city... A T6-4C and U2-4C should have a different lumen rating, but they listed them at the same lumen rating, so, what is the right spec, what is the wrong spec or is the whole thing just made up? Wires crossed? Mis-labeling? Hhhmmm. FT can always blame the supplier.
If the bin/tint info is correct, this is great news to get a neutral tint without sacrificing lumens, so the U2-4C is the superior one, if you can believe that... 
I'm going to want to see reel serial numbers, etc. if I am going to believe the Bin and tint.
Odd that this tint in the U2 bin isn't listed in the .pdfs, 'specially since they were just updated 2 weeks ago.
ahso so desu ka, but those aren't the Chinese tints.
Of course, those are different and kept in secret locations, protected by secret squirrel.
Are you hiding you are actually Japanese OL...?
Anyway, I prefer the 4c tint over a 3c, so if the U2 is really a 4C, that's great news. If not, I would just buy another T6 4C.. because it's not only about lumens..
This.