Hatches are easy to install, and mount vertically or horizontally (invisible fasteners when cover is closed). 180 degrees opening, weather tight seal, reinforced with textured non-skid surface. UV resistant. 1/2" Closed height. ID 11-1/8" x 11-1/4" OD 14-5/8" x 14-3/4" Cut Out 11-3/4" x 11-3/4" Color White