Keralastic is a premium-grade, high-performance, second-generation "flexible" acrylic latex additive used in the Kerabond/Keralastic™ and Kerabond T / Keralastic systems. This highly recommended additive enhances bond strength, flexural strength, elongation and freeze/thaw durability. To ensure proper flexibility, always use a latex additive when using a dry-set mortar for applications over plywood and for setting nonvitreous, semivitreous, vitreous and impervious tiles.