Ardex X 90 Outdoor™ MicroteC3 Rapid-Set, Flexible Tile and Stone Mortar provides maximum weatherproof protection against the harshest elements for outdoor tile and stone installations. Featuring a revolutionary weatherproof technology, it delivers full protection against the harshest weather conditions and maximum levels of efflorescence resistance for exterior tile and stone installations. It sustains the highest levels of freeze/thaw resistance, tested at 150+ freeze thaw cycles, which exceeds the ANSI 118.15 standard requirement of 20 cycles. It also features outstanding rapid-setting properties, even at temperatures as low as 40°F.