Includes 3/8 Drive Universal Impact Sockets. Sizes: 10 to 19 mm. SuperTorque lobular openings for greater turning power without deforming the fastener. Designed for maximum engagement on 6 point fasteners. Suitable for use with pneumatic and electric impact wrenches. Specially heat treated for impact use to provide long life, safety, and durability. Drive end features pin retention hole and groove