The Capri Tools external star sockets are made for the most demanding professionals. Each of our sockets is made from custom forged steel that underwent a proprietary heat treatment process and precisely machined to perform in toughest situations. We use premium Chrome Vanadium steel tempered with our proprietary heat treatment process to make these sockets. They are durable and withstand more torque. Each item underwent careful polishing and protective plating process to achieve our own chrome finish. The WaveDrive design grips fasteners more tightly than traditional design, preventing fastener rounding and giving you more leverage. Meets and exceeds ASME B107.110 standards. Set includes (13) external star sockets: 1/4 in. drive: E4, E5, E6, E7, E8, 3/8 in. drive: E10, E12, E14, E16, 1/2 in. drive: E18, E20, E22, E24.