Rubber drain cork for the stern of the Old Town Cricket and Sandpiper sit-on-top kayaks, circa 2010. May fit other Old Town and Dimension brand sit-on-top kayaks of years past. Assumed to fit some Sun Dolphin kayaks. Fits into a 5/8 inch hole on the stern of the kayak. Made of soft black rubber, tapered tip with a wide 1 inch flange on top. Has a sealed ¼ inch hole on top for flexibility. Overall length is 1 ¼ inches. Sometimes called the 5/8 inch Air Chamber Plug part number 6501385, Old Town Rear Drain Plug part number 01.1315.0411, or Sea-Dog Neoprene Plug part number 540100.