Schluter FAST-SET is a specialized, fast-setting modified thin-set mortar for use as a bond coat within tile assemblies that is optimized for use with Schluter membranes and boards. Schluter FAST-SET is smooth and creamy, as well as easy to handle and spread. It is sag-resistant and ideal for setting tile on both horizontal and vertical surfaces. Schluter FAST-SET is suitable for use with ceramic, porcelain, and stone tile, including large and heavy tile, in conjunction with Schluter-Systems