Gearing up for crevasse rescue is something you need to do all at once (half a pulley system won’t rescue anybody). Petzl makes it easy with a Mini Traxion (self-jamming pulley), an Oscillante pulley, a Tibloc ascender, two locking carabiners, and a 120cm sling.
It has everything you need for self-rescue or hauling a partner out of a crevasse. Bonus: a small skills card illustrating key techniques—good for when you freak out. Just don’t pack the kit it in its case; you’ll waste minutes digging everything out. Rack it on your harness.