Polymer-modified for strength, just add water. Adheres to most surfaces and types of tile. Bonds well to vitreous, semi-vitreous or absorptive tile: ceramic quarry, cement; impervious porcelain tile, glass mosaics, brick and mini-brick, precast terrazzo, and natural stone tile. Fast setting even in cold weather. Exceeds ANSI: A118.4 and A118.11. Covers 80 - 90 sq. ft. per 50 lbs. when applied with a 1/4" x 1/4" x 1/4" square-notch trowel.