100% Silicone Rubber window, door and siding sealant is a durable, 100% waterproof and weatherproof sealant for sealing out drafts, water and moisture around windows, doors, siding, gutters, flashing, pipes, vents and more. It stays flexible to withstand expansion and contraction without cracking or losing adhesion. Cured sealant is mould and mildew resistant and is for interior/exterior use.