Natural Light Tubular Skylight 18 inch model Large aperture for homes and commercial buildings built at 24 inch on center framing construction. Skylight Illuminates up to 500 square feet - equivalent up to 1,000 watts of light under full Sun Comes with Natural Light's 25 year product warranty. Highly reflective light pipe will not delaminate, yellow, crack or peel. Designed for use on pitched Fiber-glass asphalt shingle roofs.