These locks are mounted on the outer edge of a truck and are swung out of the way when not in use. Swing out feature makes them desirable for use in areas of rough floors, door sills, ramps, etc., which might damage conventional position locks. Retractable position locks are swung into position and engaged by foot pressure.
Used in conjunction with casters of similar heights. When pedal is depressed pad extends to floor. Spring loaded mechanism creates forceful resistance with the floor.