Professional, Extra Smooth, Large-and-Heavy-Tile Mortar with Polymer Keraflex Plus is a highly versatile, nonsag/nonslump, large-and-heavy-tile mortar and thin-set mortar for tile and stone installations on floors, walls and countertops. This polymer-modified mortar is formulated with Easy Glide Technology for ease of application and offers excellent adhesion to substrates and tile. It can also be used as a mortar over uncoupling, crack-isolation, sound-reduction and waterproofing membranes.