GE Silicone 1 All Purpose is a 100% silicone and 100% waterproof sealant ideal for a wide range of projects exposed to harsh weather from the attic to the basement. Permanently flexible, it stretches and moves with the house and will never break down due to ultraviolet rays or freezing temperatures. Formulation is resistant to unsightly stain causing mildew growth. Guaranteed for as long as you own your home.