The Altus hatches are sturdy, ocean-rated low profile hatches that project only 13/16" (21mm) above the deck.They are CE classified A II, which means they are designed for ocean use and can be fitted on deck. These hatches are provided with carefully designed hatch adjusters which are both stylish andeasy to operate.The Altus hatch can be opened from inside or outside the boat. They can also be left locked--either completely watertight or in a ventilation position. The frame profile is satin anodized aluminum. The acrylic is 3/8" thick and the color is dark smoke. An interior trim and screen are available separately for each hatch.Key FeaturesCan be opened from inside or outside boat to 120Frame height above deck measures only 13/16" (21 mm)Friction hinges keep hatch open in any position without the need for staysEasy-to-operate hatch adjusters allow lid to be held open at any angle through 90Hatch can be closed completely and locked watertight, or secured with narrow air gap for ventilationAltus Hatch Selection ChartStyleClassification (CE)Overall DimensionsCutout Size2626Ventilation13-1/4" x 13-1/4" (334 mm x 334mm)10-1/4" x 10-1/4" (260 x 260mm)D420"D" Shape Ventilation19-5/16" x 12-13/16" (491 x 326mm)16-7/16" x 9-15/16" (417 x 252mm)4242Ventilation19-1/2" x 19-1/2" (495 x 495mm)16-9/16" x 16-9/16" (421 x 421mm)4633Ventilation20-7/8" x 15-13/16" (531 x 401mm)18" x 12-7/8" (457 x 327mm)4747Escape21 7/16" x 21 7/16" (544 x 544mm)18-1/2" x 18-1/2" (470 x 470mm)5038Ventilation22-7/8" x 17-3/8" (581 x 451mm)19-15/16" x 14-13/16" (507 x 377mm)5151Escape23-1/16" x 23-1/16" (585 x 585mm)19-15/16" 19-15/16" (507 x 507mm)D520"D" Shape Escape23-5/16" x 20-5/8" (592 x 524mm)20-3/8" x 17-11/16" (518 x 450mm)6363Escape27-5/8" x 27-5/8" (701 x 701mm)24-11/16" x 24-11/16" (627 x