The Petzl MOBILE pulley weighs 68 grams and handles ropes from 6 to 13 millimeters, so one pulley covers most of the diameters a crevasse rescue or hauling system calls for. Aluminum and stainless steel construction keeps it durable at that weight, and attachment holes sized for standard carabiners let the pulley rotate freely under load. What Our Gearhead(R) Experts Are Saying:"I add the MOBILE into a loaded haul system without unclipping a single carabiner. The side plates swing open around the rope already in the system, so I'm rigged and hauling again in the time it takes to open and close two plates."