Provide positive locking in quick change applications where there is frequent insertion and removal of a fastener. They allow for consistent fastening force, eliminating the chance for under or over tightening by the operator. The flat design with recessed knob and body ensures minimal interference. They are designed to be used with QCFC-B receptacles (sold separately). The fastener is mounted to the fixture and the receptacle is mounted to the base. As the fastener is inserted into the receptacle, the pins on the fastener align with the grooves in the receptacle. The spring in the fastener allows for a range of fixture thicknesses 6mm or more. The fasteners are marked with “ON” and “OFF” indicators to show the position of the fastening pins. Four socket head cap screws for mounting are included (M2.5X0.45-5L). The body, knob, spring and screws are made from stainless steel.