The Truvativ/SRAM PowerSpline bottom bracket features a proprietary spline design used with many OE spec moderately priced TruVativ cranks. A tough bottom bracket that will go as hard as you Heat treated chromoly 12-spline spindle Able to go the distance with even the most demanding riders Crank bolts are included Spindle Interface Type: Truvativ/Sram Power Spline BB Shell Width: choose; 68mm, or 73mm Bottom Bracket Shell I.D.: 1.37 BB/Frame Interface: English Weight: 363g. Color: Black