Swanlake 3/8" Drive Impact Socket Set, 50-Piece Standard Sae, Universal Joint High quality forging, forged from heat treated chrome vanadium steel, each socket surface treated with corrosion resistant black phosphoric acid to prevent oil and rust. Product specification includes 3/8-Inch Drive Ratchet Handle, 3" and 6" drive impact extension bar, 3/8" universal joint, 1/2" to 3/8" reducer and the following socket sizes: SAE, Deep: 5/16, 3/8, 7/16, 1/2, 9/16, 5/8, 11/16, 3/4 (inches), Shallow: 5/16, 3/8, 7/16, 1/2, 9/16, 5/8, 11/16, 3/4 (inches) ,Metric Sizes: Deep: 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19,21,22mm, Shallow: 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19,21,22mm Laser marking, each with a clear laser size mark, makes it quick and easy to select even in dim light. Customized storage boxes, each with a designated slot, so that the socket does not fall off easily. Sizes are also printed next to each card slot for easy identification. 6-point socket design expands the contact surface between the socket and the fastener, increasing the locking force, reduces wear and prevents rounding off at corners