3M Marine Grade Clear Silicone Sealant This high quality silicone sealant is a one-component cure, sealant engineered to withstand the harsh marine environment. This weather-resistant sealant is formulated to resist mildew and form a non-yellowing seal for above waterline applications. In addition, this marine sealant is high-temperature resistant and remains flexible even after years of exposure. The non-shrinking and non-sagging properties of this product offer simple and efficient application