The American Rescue Systems descender is solid, well made, and very heavy. The central rib is 13 mm. aluminum with five aluminum bollards bolted to each side with 3/8-inch (9.7 mm) Allen bolts. The side pieces are steel, and pivot at the top bollard. When closed, the grooves in the side plates engage the knob at the bottom to prevent lateral motion. The carabiner passes through both side plates and the central rib, so the rope cannot be removed under load. This also means that the friction cannot be changed under load; however, with this arrangement, opening the side plates under load would allow the rope to fall out. The top of the rib is cut into a T-shape to provide a point for tying off.
This device is well-suited for lowering heavy loads, but is too heavy to be considered as a personal descender.
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©2007, Gary D. Storrick