When the SSC-P7 lights first came out all the manufacturers worked hard to make sure they worked. I only read of 1 DOA light in the first 2 months.
The quality seem to go downhill on some models lately.
A 1*18650 light in all 3 DX reviews the customer had to fix problems before the light would work.
A 2*18650 light 2 CPF members reported the light died soon after arrival.
It is buyer beware time. Read the reviews at DX and here for LACK OR RELIABILITY reports before buying.
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The SSC-P7 uses up 10+ watts of energy. The smaller brighter lights can get too hot to hold on max (even my big 3C P7 M@g gets hot all the way to the tailcap though I have no problem holding it). Runtime is under 1 hour on max. That is why I recommend getting a 5 mode. Run in medium normally. Go to max only when you need to. The circuitry seem to limit the amperage so they are not the brightest.