Cast Almag with stainless-steel handle Watertight to 30ft. head 4 dog sealing system Optional steel mounting ring Designed to meet requirements of US Coast Guard, ABS, Lloyds of London and British Dpt. of Trade Opening Size: 15" X 24" Oval Cutout: 20-1/2" x 26-3/4" OD Deck Flange: 23-1/2" x 30-1/2" Extends below Deck: 5" Mounted Ring: Aluminum Hinged: Yes