The Alptech ABS works on a different principle than most belay devices. The ABS is used with an HMS carabiner. When the climber falls, the carabiner pulls the rope into a v-groove, providing friction to stop the climber.
The
instructions that came with my ABS state "The A.B.S. blocks
the rope without the belayers intervention. If the climber falls,
let go of everything, the A.B.S. will automatically lock. Important!
During a fall do not hold the rope for risk of burning your hands
and causing a longer fall."
Let go of everything? Let go? Actually, I believe it will work, but I haven't been able to test it, since my friends don't want me to just let go.
The Alptech ABS is protected by U.S. Patent 5,850,890.
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©2007, Gary D. Storrick