The diameter and type of cord used to make a friction hitch must be selected according to the rope it will be used on. Holding power and ease of release can be adjusted by changing the number of wraps.

Autoblock

Easy release, locks in both directions.

Prusik

Locks in both directions.

【转自：https://www.petzl.com/US/en/Sport/Friction-hitches?ActivityName=Rock-climbing】