Glass Mosaic Tile (GMT) Thin-Set Mortar is the ultimate one-step polymer fortified thin-set mortar specifically designed for outdoor and wet environments. GMT Thin-Set Mortar provides superior adhesion to glass, mosaic tiles, porcelain, ceramic, and natural stone. Its unparalleled proprietary formulation makes it the perfect choice for setting tile in swimming pools, spas, water features, and other areas with submerged applications. GMT Thin-Set White Mortar produces an ultra-white finish that will enhance the look of glass, mosaic tiles, and any translucent tile or stone. GMT is now also available in gray. For use in both commercial and residential applications.