The Exo Terra Stone Back Panel for terrariums is easy to cut and has an incredibly natural look. It creates a multi-dimensional environment, ideal for reptiles to climb on or can simply be used to brighten up the terrarium. Its color and texture, like all Exo Terra terrarium decorations, blend seamlessly into the environment, whether humid or dry. The grooves on the back panel are designed to conceal cables or tubing for pumps or Heat Wave Rock. The back panel is made of black polystyrene, so it won't be noticeable if accidentally damaged (this wouldn't be the case with white polystyrene). Polystyrene has the added benefit of providing insulation and is easy to cut to fit any terrarium size.