Bomar's Hatch Access is molded of high-impact UV-stable polypropylene. Hatch is low profile for convenient floor mounting. No screws are visible from the exterior. Hatch opens 180° and has a strong lid with support bars and double gasket for optimum sealing. New patented easy opening/closing slam latch comes standard. Hatch Opening: 27-5/16" x 10-5/16". Cutout: 28-3/8" x 11-3/8". O.D. Lid: 30-1/4" x 13-7/16". C.O. Radius: 2-1/16".