first and foremost I am no led flashlight guru. i am the one learning here. Here is my informal comparison I did with the D25LC2 xm L2 U2 and the D25LC2 xm LT6. Wthe naked eye I could not tell much difference between the two other then tint. I stood on a power line and I could see the the next pole at 550' with both of them. The only REAL difference with MY eyes was the tint. If the xmL2 is brighter my eyes could not tell the difference. I thought I would share my novice inexperienced opinion on what I saw. I don't know how I got hooked on this new hobby but it is turning out to be fun.