Deck fittings suitable to mount on a flat deck with a single fastener. A Sea-Lect, aka Sea Dog product. Common on many sea kayaks. The four holes can take a ¼ inch line in each. A single number 10 flat head screw can secure this to the deck. 1 1/2 inches across by 3/8 inch high. Made of black nylon plastic. Sold six to a pack. (Sea-Lect part number K736530-1)