WALGUN PF4124 ceramic bottom bracket is made of 6805 sealed ceramic bearings and 7075 aluminum alloy (full CNC machining). Its BB standard is BB86/BB92, The 41mm outer diameter of PF4124 is compatible with 86.5mm (road) and 91.5mm (mountain) bicycle frames, and is compatible with 22mm 24mm spindle bicycle cranks (Shimano Ultegra Dura ace 105 Sram Gxp Bicycle Crankset).
