1/2′′ Tongue & Groove Hollow Panels These highly-reflective panels are ideal for high-moisture areas because they are water-proof! Panels install quickly and easily, with no exposed fasteners. Available in widths of 12- and 24-inches and cut to length from 4 to 20 feet, to fit your building. These panels are stain-resistant, low- maintenance and easy to clean (when required). Use in self-serves, automatics and tunnels. Colors available.