Sizes: 5/16″, 3/8″, 7/16″, 1/2″, 9/16″, 5/8″, 11/16″, 3/4″, 13/16″, 7/8″, 15/16″, 1″ Made from high quality alloy steel (chrome-molybdenum). Transfers the pressure from the thinnest part of the socket wall toward the thicker section, resulting in increased strength. Allows up to 20% more torque to be applied than on standard impact sockets. The shift in pressure allows us to reduce the socket wall thickness, increasing access to tight areas. Molded Storage Case. .