Ultraflex LFT Rapid is a premium, rapid-setting, nonsag medium-bed and thin-set mortar for large-format tile and stone for interior/exterior floor, wall and countertop installations. This mortar has a high content of unique dry polymer, resulting in excellent adhesion to the substrate and tile. Ultraflex LFT Rapid is FastTrack Ready™, allowing grouting in 3 to 4 hours.