T-H Marine Sure-Seal Deck Plates. These Deck Plates feature T-H Marine"s Sure-Seal design... a fully overlapping lid and a positive "O" ring seal for a watertight fit. There are no visible mounting fasteners. Your Deck Plates are totally UV and chemical stable and require no tools for opening. While you"re at it, get some Versatubes for your boat to protect your keys, flares, charts and anything else that might get damaged from moisture. Versatubes include a 4" Sure-Seal Deck Plate to keep the water out. State Size and Color. Order Now! T-H Marine Sure-Seal Deck Plate