Schluter Systems Kerdi-Board Rectangular Bench 38-in x 11-1/2-inKerdi Board SB is a prefabricated shower bench designed to integrate with the Schluter Shower System. It is lightweight, waterproof and ready to tile making installation quick and easy. The bench is made of Kerdi Board and comes with Kerdi Kereck waterproofing corners. Rectangular bench made of Kerdi Board Bench dimensions are 38 in x 11 1 2 in x 20 in Sloped surface to prevent water accumulation Bench includes preformed 90 inside and outside Kerdi