The Park Tool FR-5.2 Cassette Lockring Tool Heat treated alloy tool steel, one inch base fits wrench or bench vise. Thin wall construction allows use without removal of cones and locknuts. The FR-5 has 12 splines that are approximately 23.4mm across.  Park Tool FR-5.2 Cassette Lockring Tool Features This new updated FR-5.2G now fits the SRAM® XX1® 11-speed cassettes 12 splines, 23.5mm diameter Also fits some Shimano® disc brake lockrings Made in the USA and covered by Park Tool's legendary limited lifetime warranty