Updated FR-5.2G has longer splines than previous version for better engagement Fits Shimano, SRAM(including 1x), SunRace, SunTour, Chris King, and other cassette lockrings Also fits some Shimano Center Lock disc rotor lockrings Heattreated alloy-steel construction Thinwall design allows for use with cones/locknuts 25.4mm (1") base/head fits FRseries wrenches or vise Retailers are not permitted to sell on the Amazon.com marketplace unless authorized in writing by Park Tool