3M Marine Adhesive Sealant 5200 is a one-component, high-strength, moisture-curing, gap-filling polyurethane gelcoat and fiberglass. It cures to form a firm, rubbery, waterproof seal on joints and boat hardware. 3M Marine Adhesive Sealant 5200 is designed to meet the high demands of the marine environment, making it ideal for creating tough bonds resistant to saltwater and weathering. This sealant provides an exceptionally strong solution for marine conditions as well as flexibility.