Beckson Smooth 4" Screw-Out Marine Deck PlateThe 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 Buttress Thread; Innovative Gasket; Back-Up Sealing Wall; Self-Aligning Center; Certified Water-Tight; Lightweight, High Quality ABS Marine Plastic; Corrosion Resistant; Available In Multiple Colors;