The Beckson Screw-Out Plate was designed to provide access without the use of tools, with a single start non-jamming (no cross-thread), extra strong, self-cleaning buttress thread. They incorporate a self-aligning center and an innovative gasket to assure a watertight seal. A back-up sealing wall leaves the plate watertight, even if the gasket is removed. Beckson's clear center plates permit observation of controls or gauges and visual inspection without the necessity of removing the center. Deck plates are used for access to shut-off valves or back-fastenings, inspection, and clean out for tanks and compartments. A screw-out plate should be used in compartments where a change in air pressure due to temperature or oil canning can occur.