Our 50-Year Silicone Sealant is an energy-efficient sealant that remains permanently flexible. It is waterproof and will not shrink or crack. It can be applied in temperatures ranging from -30°F to 140°F. The sealant is ideal for window or door seals and can also seal window sills, baseboards and other gaps and openings where a long-lasting professional-grade sealant is needed. It can be used for both interior and exterior applications and resists UV, sleet, snow and ozone.