Formulated to create a long-lasting watertight and weatherproof seal with superior flexibility and adhesion to a variety of building materials making it ideal for filling and sealing cracks and gaps. When cured it is mold and mildew resistant and will not crack or shrink. Unlike acetoxy silicone sealants DAP® Silicone Plus™ Premium Silicone Rubber Concrete and Masonry Sealant is low in odor. Meets ASTM Specification C 920, Class 25, Type S, Grade NS. Backed by a Lifetime Guarantee.