Bomar Commercial Grade Cast Aluminum Hatch 24 inch Square 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: 24 inches x 24 inches (610 millimeters), Outside Deck Flange: 31 inches x 31 inches (787 millimeters), Cutout: 27 inches x 27 inches (685 millimeters), Extends below deck: 7-1/4 inches (185 millimeters), Weight: 45 pounds. This model does not open from the inside.