Narrow Wide tooth profiling ensures ultimate chain retention Attaches as part of the RF Cinch system (using common Park BBT-22 bottom bracket tool) - allowing to switch between DM rings/spiders with ease Utilizes RF proprietary spline design 7075-T6 aluminum, aerospace grade strength Stiff 4mm plate thickness to transfer loads without flexing Compatible for 9, 10, 11 and 12 speed.specifications:- Built For: XC/Trail/AM/DH- Weight: 33g (24T) - 112g (42T)- Compatible With: Race Face cranks with CINCH System Interface- Size: 24T, 26T, 28T, 30T, 32T, 34T, 36T