Kincrome's 10 Piece Impact Socket Rail 3/8" Drive (Imperial) is crafted from Molybdenum (Cr-mo) Steel, ensuring a lifetime of toughness. The 10 Deep Imperial Impact Sockets are supplied on a Clip Rail and include sizes 5/16, 3/8, 7/16, 1/2, 9/16, 5/8, 11/16, 3/4, 13/16, 7/8".