The 3/8 in. Drive Shallow, Semi-Deep and Deep Impact Socket Set is a collection of most frequently used 3/8 in. drive impact sockets in SAE sizes Premium Chrome Molybdenum steel tempered with our proprietary heat treatment process to withstand more torque from power tools Expertly coated with manganese phosphate, the preferred coating in military and aerospace; it offers superior protection and corrosion resistance compared to black oxide coating on other impact sockets 6-point WaveDrive design grips fasteners more tightly than traditional design, preventing fastener rounding and giving you more leverage 40-piece set includes (12) 3/8 in. drive shallow impact sockets, (12) 3/8 in. drive semi-deep impact sockets, and (12) 3/8 in. drive deep impact sockets in the following sizes : 5/16, 3/8, 7/16, 1/2, 9/16, 5/8, 11/16, 3/4, 13/16, 13/16, 7/8, 15/16, 1 in., (3) 3/8 in. drive impact wobble extension bars: 3, 6, 10 in., and (1) 3/8 in. drive impact universal joint