These head cap screws can come with large cylindrical heads that have recessed hex-shaped drives. These make them suitable for applications where clearance is limited, and sockets and wrenches can't be used. Hex-shaped recesses in the head provide a driving surface that has increased protection against damage and has six sides of contact surface for more torque. We offer socket head cap screws in alloy steel. They are the strongest of all steel types and the high tensile strength provides excellent resistance to galling, fatigue and wear.