Roberts 5900 is a high performance, ready-to-use Type I Mastic for installing ceramic, porcelain, natural stone, quarry and mosaic tile on floors and walls. It may be used for countertop, backsplash and shower wall installations, too. 5900 spreads effortlessly, sets quickly and is easy to clean up. Type I Mastic for floors and walls. Spreads easily, dries fast, simple cleanup. Premixed and read-to-use. Meets ANSI A136.1 Type I and II specifications.Traffic Residential/Light Commercial.