Nature's Cooling Solutions Room Air Conditioner - Side Panels (17.5) Easy to install in existing side panel frames to replace accordion panels. Cut to size with scissors and start saving energy. Semi rigid panel stays snuggly in place without the need for self-stick side channels Water proof  Side panels are closed cell foam that will not absorb water. Eliminates the mold issue common with open cell sponge like foam. Panel made of 17.5x9.6x3/4 inch closed cell foam with superior insulation properties that will reduce energy loss. Side panels provide 50% more insulation than standard panel. Increased panel thikness decreases outside noise; Uniform look provides improved aesthetics; Moisture and weather resistant Far Exceeds the ENERGY STAR Room Air Conditioner V 4.0 Installation Criteria effecive October 26, 2015