Though deck plates are no new invention, but Beckson was the first to conquer all three safety features. -First, a cover that would not open unexpectedly. -Second, maximum watertightness. -Third, prevent jamming closed or cross- threading that would prevent a cover from being closed. 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 patented back-up sealing wall leaves the plate waterproof, 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. Deck plates also are used for access, inspection,and clean out for tanks and compartments, or just as a general access for shut-off valves or back- fastenings. Clear center plates permit observation of controls or gauges and visual inspection without the necessity of removing the plate. Design Patented and U.S. Pat. Nos. 327,246 4,246,859 4,280,434