Bri-Rus Skylight Dome. Skylights are made of high performance thermoformed polycarbonate to be long-lasting and easy to clean. When choosing a Skylight, measure your rough hole opening as well as the overall exterior size. There is a size to replace most manufacturer's original equipment. Skylights sit directly on your RV roof. If necessary, an inner garnish is available to finish the inside hole (order separately). No metal flange is used with these single pane skylights. Use a skylight size that is equal to or greater than your hole dimensions. Note: inners must be the exact size as the hole you are working with. Skylights include care instructions and include a tube of approved urethane sealant that must be used when installing. Neo Angle Skylight with one angled corner; to measure a Neo Angle Skylight, the longer side at a 90 degree (X) is the first value and the shorter is the second value (Y), or distance from the end corner of a long side to the beginning of the angle. Smoke color.