This is a professional quality 13-piece set of 1/4" drive deep socket bits. These sockets are drop forged, hardened, and tempered chrome vanadium steel. The socket length is approximately 50mm and they come in sizes 4, 4.5, 5, 5.5, 6, 7, 8, 9, 10, 11, 12, 13, and 14mm. They feature a knurled grip around the circumference for added hand grip and a high mirror polished finish. The set is supplied in a plastic storage tray to keep the sockets conveniently grouped. The MPN for this set is 1388.