Permatex Gasket Maker Ultra Copper gasket silicone is a flexible sealant used to create airtight and watertight seals between surfaces. It is commonly used in engines, plumbing, and household repairs. This material can withstand high temperatures and resists oil, water, and chemicals. Gasket silicone is easy to apply and dries to form a strong, rubber-like seal. It helps prevent leaks and improves the durability of mechanical joints.