The Truvativ Powerspline Bottom Bracket features a heat-treated, chromoly 12 spline spindle, a Chainline control stop and sealed cartridge bearings. Weight: 340g. The Truvativ Powerspline bottom bracket will only fit Truvativ 12 spline chainsets. This bottom bracket is intended for road or trekking use. Truvativ Powerspline Bottom Bracket Features Heat-treated material Chromly 12 Spline spindle Chainline control stop Sealed cartridge bearings