Pedros Pro BB Socket 5pc SetThe solution to the ever growing number of threaded bottom bracket standards flooding the market Designed to accept Pro BB Inserts via magnetic connection, allowing for quick, effortless swapping 7075 T6 aluminum socket is fully machined to precise tolerances 3 8" square drive for use with torque wrenches, 24mm external drive for use with Pedros Pro Socket Handle and pedal wrenches, and internal M12 thread for use with the Pro BB Socket Holder 01: