The Clearseal black foam base mat is an alternative to the white polystyrene tiles normally used between an aquarium and the surface that it is sited on. Manufactured in a dense black foam, it will even out slight imperfections under the aquarium however this is not a substitute for a flat and even surface. If the original surface is not flat, damage may occur to the aquarium. These base mats can be easily cut to size for non-standard aquariums. They are also recommended for all-glass vivariums, terrariums, and other glass tanks. Available in 6 different sizes.