Bomar Commercial Grade Cast Aluminum Hatch 20 inch Round 4-Dog Flush Mount Watertight. Hatch is made of Almag-35 Aluminum and has outside opening stainless steel t-handle. This hatch is not hinged. Hatch Opening: 20 inches (508 millimeters), Outside Deck Flange: 26-1/2 inches (675 millimeters), Cutout: 23 inches (585 millimeters), Extends below deck: 7-1/4 inches (185 millimeters), Weight: 32 pounds. This hatch does not open from the inside. An optional inside handle is available.