Made for the most demanding professionals, each of our bit sockets is made from custom forged premium steel that underwent proprietary heat treatment and precisely machined to perform in toughest situations. Premium S2 steel forged bits are exceptionally strong and durable. These S2 steel bits withstand high torque and do not twist, protecting both the bit and the fastener. Chamfered end to ensure a smooth fit onto fasteners. Premium Chrome Vanadium steel sockets plated with our SmartKrome protective plating are durable and corrosion resistant. Single 1/4 in. drive, long 4 mm hex bit socket (3-1/16 in. long bit). The Capri Tools bit sockets are made for the most demanding professionals. Each of our bit sockets is made from custom forged steel that underwent a proprietary heat treatment process and precisely machined to perform in toughest situations. Premium S2 steel forged bits are exceptionally strong and durable. They withstand high torque and do not twist, protecting both the bit and the fastener. All bits feature chamfered end to ensure a smooth fit onto fasteners. The sockets are constructed with premium Chrome Vanadium steel and plated with our own SmartKrome protective plating. They are durable and resist corrosion. Meets and exceeds ASME B107.110 standards. Single 1/4 in. drive, long 4 mm hex bit socket (3-1/16 in. long bit).