A premium, multi-purpose, polymer-modified, thin set mortar; for interior & exterior installations, when setting all types of ceramic, porcelain, granite, slate, marble, limestone, and dimensional stone. To be used over properly prepared concrete; structurally-sound, exterior grade plywood ( interior / dry use only ); cementitious backer board; Bostik Ultra-Set Advanced, Bostik Black-Top, Bostik GoldPlus; and existing, well-bonded vinyl composition tile ( VCT ) or ceramic tile.