Stone resin shower trays are the only way to go for a permanent shower enclosure. They’re stronger than acrylic, and thanks to their stiffness they’re easier to install because twisting or bending isn’t possible. When installed flat to the floor the sound insulation is better than acrylic, and finally the lack of movement in the tray means a better, more secure water-tight seal around the edge of the tray and the edge of the waste.