I just received a bunch of flashlight parts I ordered from Kaidomain.com. Among them, four Cree XLamp XR-E LEDs, Q2 and Q5 bins. I thought I’d mod my Ultrafire C2 flashlight that has a P4 bin Cree with the Q5. I can’t tell the difference between the Q5 and Q2 by looking at the two. I guess I have to do some kind of measurement of current and light output. The Cree XLamp LED Q5 will put out 107 Flux (lumens) when driven at 4 amps – that’s very bright.One of the four LED’s seems to have a manufacturing defect – see the material in the upper left corner of the chip in the photo?Two people who offered me help on the Candlepowerforums.com came up with different answers. jtr1962 says it’s the result the dome is starting to detach – he called it internal separation of the silicon filler. WeLight theorized that it was a manufacturing defect and I should return it. I don’t know much about these high power LED’s but I’m learning.