Twist-Out Deck Plate The Beckson Twist-out Deck Plate is designed to conceal its mounting fasteners under the quick twist cover. The low profile cover is self-centering, and quickly locks in place with a 1/8 twist. Three seperate sealing areas, each designed to chase water away from the plate opening, assure a watertight closure. The bayonet threads are non-jamming, self-cleaning and lift at the center for easy removal. O.D.: 7″ I.D.: 5″ Hole Cut: 5-1/2″