Sockets screws have a "hex" drive - a hexagonal socket in the head (internal-wrenching hexagon drive). The term hex-head is sometimes used to refer to this type of drive, but this use is not consistent with its more conventional use referring to external-wrenching hexagons. In the fastener industry, the terms socket head or hex socket head are generally used for the driven part of the driver-driven pair. The contact surfaces of the fastener are protected from external damage. Hex socket drives also allow for headless screws, with the drive set into the shaft of the screw itself.