Diameter of bore: 24.2mm; Bore depth: 30.5mm; Made of high quality steel; Suitable for Shimano Isis, fsa, raceface, truvativ of 20 spline bottom bracket; It can work with 24mm wrench or 1/2" ratchet wrench; When installing, the crank side should be clockwise while the chain wheel side should be anticlockwise.