The 1/4 Drive 6 Point 4mm Socket by Great Neck feature an exclusive Posy-Grip No-Slip design. This socket wall design provides superior gripping power without rounding the fastener points. Torque is applied to the walls of the fastener head. This socket also features high carbon steel and high quality chrome vanadium steel for strength, durability and resistance to corrosion. Identification stamping shows size and brand for faster socket selection.