Beckson Smooth 4 Screw-Out Marine Deck Plate The Beckson Smooth 4 Screw-Out Plate is designed to provide access with a single start non-jamming, self-cleaning, extra strong buttress thread, without the use of tools. With a patented back-up sealing wall, the plate remains watertight even if the gasket is removed. A screw-out plate should be used in compartments where a change in air pressure due to temperature or oil canning can occur. Features No Cross-Threading Non-Jamming Self-Cleaning Buttres