Magnetic plug and play system replaces eight BB sockets. Included Pro BB Socket Cup and eight Pro BB Inserts pack down smaller than two traditional BB sockets.. 7075 T6 aluminum socket is fully machined to precise tolerances for an exacting professional-level fit.. Features a 3/8″ square drive for use with torque wrenches, a 24mm external drive for use with Pedro’s Pro Socket Handle and pedal wrenches, and internal M12 thread for use with the Pro BB Socket Holder.. Inserts are precision laser cut tool steel with optimized heat treatment for precise fit and superior tool life. Includes Pro BB Socket Cup, Pro BB Inserts: Shim. 16×44, Shim. 16×41, Shim. 16×39, BSA30/DUB 12×46, T47 16×52, T47 12×52, T47 16×48.5, & Prax. 12×49, and Pro BB Socket Holder, all packed in a premium EVA foam holder.