The Park Tool FR-5.2 Cassette/Rotor Lockring Removal Tool is made from heat-treated alloy steel with a one-inch base. Thin wall construction allows use without the removal of cones and locknuts. The FR-5 has 12 splines that are approximately 23.4mm across. Features: Fits most 7-12 speed cassette lockrings You can use a quick-release skewer to hold the tool in place and snug to cogs when loosening; for solid axles, use the axle nut Hex-shaped base of tool fits 1" (25.4 mm) socket or wrench. Can also be clamped in a bench vise Specifications: Outer Diameter: 23.4mm (Approximate) Center Bore (For Axle Clearance): 12mm Splines: 12 Compatibility: Fits 12-spline tool fittings with an approximate outer diameter of 23.4 mm Fits cassette lockings from Shimano, SRAM, SunRace, SunTour, Chris King, and more Fits disc brake lockrings and locking adapters with 12 internal splines (Shimano type) Fits top cap of some RockShox suspension forks including Pike, Lyrik, SID, Revelation, Reba, and Paragon