All models of bottom bracket sockets are precision CNC machined tools for installation and removal of different external bottom bracket cups. They are made of aluminum billet and anodized red for durable finish and precise fit, that won´t damage aluminum external bottom bracket cups. Knurling on the side of the socket creates better grip when threading cups by hand, meanwhile 1/2˝ square drive makes it easy to use with torque wrenches, ratchets and fixed handles.