Premium, Rapid-Setting Tile Mortar with Polymer Ultraflex RS is a premium-grade, single-component, high-performance, polymer-modified, rapid-setting thin-set mortar for interior and exterior installations of tile. This mortar has a high content o f unique dry polymer, resulting in excellent adhesion to the substrate and tile. Ultraflex RS is a FastTrack Ready™ product, allowing grouting in 2 to 3 hours. It can be used for both interior and exterior installations of tile in most residential fl oor and wall applications. In commercial applications, use on interior floor and wall installations and exterior floors. Ultraflex RS meets or exceeds ANSI A118.4F, ANSI A118.11 and ANSI A118.15F requirements for fast-setting mortars when mixed with water.