I am going to upgrade a couple Convoy lights I have laying around hopefully with some xml2. I am not a big fan of Fasttech but I found this http://www.fasttech.com/products/1609/10003889/1574601-cree-xm-l2-u2-4c-1100lm-4300-4500k-led-emitter-on on their website. Has anyone confirmed that these are legit? If they are legit I might give Fasttech another chance.
I've used both the T6 3B & 4C from FT, they seem to be what they say they are. Dunno about the U2s, though.
I have one of the xml2 t6 4c from Fasttech in a Convoy s3 and to me it looks a little green. Hopefully someone that has installed one in a light can chime in.
I have used both in identical builds: https://budgetlightforum.com/t/-/23706 - 3B shown there, did another just like it but with the 4C. Doesn't look anything like greenish to me, looks nearly exactly the same tint as as the 50F MT-G2.
I also have the XM-L2 T6 3B from FT and its the real deal. Its also one of my preferred tints.
Thanks for the info guys. It would be cool if someone had a side by side comparison of this claimed xml2 u2 4c and the xml2 t6 4c.
It would take a light meter to show the difference. Your eyes wont detect it.
I’m giving fasttech :Sp another chance to win me back as a customer. I just placed an order through fasttech for this xml2 u2 4c that will be installed in a convoy s3. I already have a convoy s3 with an xml2 t6 1c that I will be taking comparison photos side by side with the xml2 u2 4c.
T6 U2 …… 4C 3B
I assume i have separated these ‘descriptors’ into groups that reflect variations of the same variable. Can someone tell me, what each of them means. Does the U for example mean something on its own, or is there only a U2, no U3 for example? Same with the T
Then the 4C etc, what do these refer to? And does the number mean one thing, and the letter another? ie: is there a 2C a 5C etc?
Im kind of aware of one of them being tints (colours of light), but then there seems to be more to it than I can see. And if only one is tint, what is the other?
Flux bin, and tint. Flux bins are just ascending and don't mean anything except in relation to the others, a T6 is brighter than a T5, U2 is brighter than T6, U3 brighter than U2, etc.
The tint corresponds to a location on this map: http://flashlightwiki.com/images/c/cb/Ansi-white.jpg
http://flashlightwiki.com/ANSI_White
and http://flashlightwiki.com/LED
Here are shots with my cellphone of the fasttech xml2 u2-4c next to a fasttech xml2 t6-1c. These are emitter swaps from identical convoy s3 lights https://www.fasttech.com/products/0/10002364/1195015-convoy-s3-cree-xm-l-u2-1b-2-group-35-mode-edc-led-
On the left https://www.fasttech.com/p/1574601
On the right http://www.fasttech.com/products/1609/10003889/1277804-cree-xm-l2-t6-1c-10w-6500k-1052lm-led-emitter
xml2 u2-4c
xml2 t6-1c
I can’t tell if one is brighter than the other. I do not have anything to measure lumens with. I have a noctigon Xml2 T6-4C coming from rmm I plan to install in a Convoy M2. I’ll post pics as soon as I receive it.
I’m pretty sure this U2 4C is just T6 4C. U2 4C doesn’t exist even in Cree’s datasheets. Probably one of FT’s suppliers lied to them. There’s no U3 in Tangsfire either - it’s just heavily driven T6.
Curious to see your comparison pics on these.
-Garry
I had actually fried the led’s on both the s3 and m2. I had dedomed the led’s and they worked for a while. I think what finally killed them was using them on my bike during the day in flash mode. The led just fell off the star most likely from overheating. I’m pretty new to this modding stuff but I was able to copper braid the springs in all my lights and this is only the second time I have swapped an led from one of my lights. I did this using a $7 harbor freight soldering iron. I also changed the exposed wires from the driver on my s3 with some 22awg silicone wire I ordered from fasttech.
+1 - no such thing as a U2 4C most likely. 22 gauge from FT - not too good, I'd stay away. Your really should use the better 200C rated silicone wire - that's what we all typically use. For LED's to fall off the star takes a lot of amps or force - really should use copper stars. Your really need to hit Richard at mtnelectronics.com for high qual parts at competitive prices.
Already ahead of you… see post #14 
I am not ordering from fasttech unless I am in no hurry to receive my order. I have placed 2 orders from RMM and plan to keep spending my money domestically. I have my eyes on a couple of items sold through illumination supply.
Cool! RMM is wayyy too accomodating. Since he is a crazy hobbyist like the rest of us, he seems to only carry stuff we are looking for... 
Convoy M2 Noctigon xml2 t6-4c
Convoy M2 Noctigon xml2 t6-4c
The picture of the M2 close up to the wall came out yellow no matter which setting I changed on my galaxy s3 phone.