A versatile, 100 percent silicone formula designed for interior and exterior applications. Ideal for most construction, remodeling and repair projects including doors, windows, siding, vents, tubs, sinks, and more. It forms a rough yet flexible seal that is watertight and mildew-resistant. Titibond 100 percent Silicone Sealant offers strong adhesion to most materials and can withstand extreme temperature changes. It has been certified to Federal Specification TT-S-001543A, Class A and passes ASTM C920 Type S, Grade NS, Class 25.