Premium, Large-and-Heavy-Tile Mortar with Polymer Ultraflex LFT is a premium, nonsag, large-and-heavy-tile mortar (formerly known as “medium-bed mortar”) and thin-set mortar designed for large-format and heavy 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. It is formulated with Easy Glide Technology™ for ease of application.