Most crevasse rescue pulleys just don't do the trick. Lightweight doesn't always equal efficient. If I have to haul someone out of a crevasse I would much rather carry a few extra grams and be able to haul without loosing all my work to inefficient pulleys while my partner is stuck in a crevasse! Enter the partner pulley, sealed bearing and super efficient. And it's barely heavier than the pulleys that have plastic sheeves and bushings not bearings. NOT GOOD OR SAFE if you ask me. If you have this, a Tibloc, and the micro traxion, you should be set for an efficient and durable system.