These retractable fasteners provide positive locking in quick change applications where there is frequent insertion and removal of a fixture. They allow for consistent fastening force eliminating the chance for under or over tightening by the operator. They are designed to be used with cam receptacles (QCTH-N and QCTH-B Series). The fastener is mounted to the fixture and the receptacle is mounted to the base. Pulling up on the handle allows the plate or fixture to slide on the base without interference from the fastener. As the fastener is inserted into the receptacle, the pins on the faster align with the grooves in the receptacle. Turning the knob one quarter turn aligns and locks the fastener into place. The fasteners are marked with "ON" and "OFF" indicators to show the position of the fastening pins. Three socket head cap screws for mounting are included (M3X0.5 - 6mm long). The bodies and shanks are made from 1045 carbon steel with an electroless nickel plated finish, or 303 stainless steel. The pins are made from 304 stainless steel. The knob is made from black plastic or 304 stainless steel.