Topaz bathtubs feature precision molding from Mustee''s premium Varistone fiberglass. The tube has structural ribbed bottom and sides to prevent sagging and the apron is supported by 2 molded fiberglass brackets. Ergonomically contoured back with a 40 degree lumbar slope. Proprietary finish creates a deep, long lasting shine, scratch-resistant surface and slip-resistant bottom. One piece molded with matching metal molds that fits standard 30''x60'' alcove.