Ignore what I said before, I think Chris is correct. From what I can make of it, it is
KL1 = Luxeon for E series
KL2 = 19 5mm's for M series
KL3 = Luxeon for older or "standard" size lights. I thought this one will also work on 1, 2, or 3 cells?
Again this is what Chris said, and again no one but Surefire knows when they will be released. I think the KL1 and KL3 will be fully regulated, anyone hear otherwise?