WALGUN PF41DUB ceramic bottom bracket is made of 61706V C3 sealed ceramic bearings and 7075 aluminum alloy (full CNC machining). Its BB standard is BB86/BB92, The 41mm outer diameter of PF41DUB is compatible with 86.5mm (road) and 91.5mm (mountain) bicycle frames, and is compatible with 29mm spindle bicycle cranks (Sram Force XX01 X1 XX1 Eangle DH DUB Bicycle Crankset).