In reply to Mick Ryan - UKClimbing.com:
Out of interest (I've never seen one let alone used one)... how do they work?
I don't mean what's the braking mechanism etc, more, how do you use them and how do they function in normal use?
If they're rated for 300lbs then presumably there's not anywhere near a 1300N upward pull when you clip on and climb?
Do they pull you up? How much, a few tens of Newtons?
If you let one go at the bottom do they just whiz away up the wall?
Do they lower you at a constant rate or accelerate/decelerate as you go?
Just trying to get an idea of what you're discussing really. Hope the guy's ok, sounds like he will be.
jk