Petzl Fixe micro pulley has a multitude of uses, but it is primary used as a slack tender on a friction hitch. This pulley has fixed anodized aluminum cheeks (hence the name fixed), with 5/8" holes for a carabiner. The aluminum sheave is 1-1/4" in diameter and held in place by a self lubricated bronze bushing. The fixed cheeks are fairly close together at the top, so you must thread a 1/2" climbing line through the side. Each pulley is individually inspected for quality and CE approved.