Line of undermount bathtubs with a rectangular inner base integrated in an expanded polystyrene structure (EPS). Adding EPS compensation panels, it is possible to create made-to-measure bathtubs both in terms of shape and in terms of outer size. Wave can be clad with traditional construction materials (such as mosaics, ceramic, porcelain stoneware), resin, or with the standard range of claddings including glass, Corian®, Makril, thermo-treated wood, cement and marble. The tub is available in three sizes: small, medium and large.