Acratech Quick Release Clamp with Spring-loaded Detent Pin, Rubber Knob, Double Speed Thread This Item Includes: Acratech Quick Release Clamp - 1/4"-20 Reducer Bushing - Detent Pin - Acratech 10 Year Warranty - Note: Requires Mounting Plate Sold Separately Acratech Quick Release Clamp with Spring-loaded Detent Pin, Rubber Knob, Double Speed Thread