The Capri Tools 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 metric sizes. We use premium Chrome Molybdenum steel tempered with our proprietary heat treatment process to make these impact sockets and accessories. They are durable and specifically made to withstand high torque from power tools. Each item is expertly coated with manganese phosphate, the preferred coating in military and aerospace, which offers superior protection and corrosion resistance compared to black oxide coating on other impact sockets. The 6-point WaveDrive design grips fasteners more tightly than traditional design, preventing fastener rounding and giving you more leverage. Meets and exceeds ASME B107.110 standards. 45-piece set includes (15) 3/8 in. drive shallow impact sockets, (15) 3/8 in. drive semi-deep impact sockets, and (15) 3/8 in. drive deep impact sockets in the following sizes : 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22 mm. Comes with a billet aluminum socket rail made by Westling Machine.