Just another word of warning for GP users. I screwed on an atty too tight and while trying to loosen the screw of the top switch, I got a nasty cut on the side of my thumb. Didn't even notice the cut until I saw blood smeared along the side of the tube.
The screws below the top cap can be very sharp. Use caution when applying pressure.
** edit ** I figured out the cut on my thumb was actually from the threads of the top cap not the screws. I was trying to screw the top cap onto a kayfun light and if you grip the top cap firmly at the threads and try to turn it, you might get cut. Hopefully no one else is as stupid as me to do this and so far it appears no one is. 
This isn't the first time I've sliced my hands with the GP. With the lux, I had the top cap on too tight and while trying to loosen it with the button off, I sliced up the side of my palm on the bottom of the tube around the threading.
The threading on the tubes can be very sharp. Use caution when applying pressure.
By cuts I mean something along the lines of a nasty paper cut,
not along the lines of losing a finger. So yeah, I'm fine and it's not a big deal but it's avoidable.
