3M ™ Marine Adhesive Sealant Fast Cure 4200FC is a one-component, medium-strength, moisture-curing, gap-filling polyurethane that delivers strong, flexible bonds to aluminum, wood, gelcoat and fiberglass. It forms watertight, weather-resistant seals above and below the waterline. In addition, its flexibility allows for dissipation of stress caused by shock, vibration, swelling or shrinking. 3M ™ Marine Adhesive Sealant Fast Cure 4200FC chemically reacts with moisture, delivering flexible bonds with good adhesion to wood, fiberglass, gelcoat, plastics and metals. This multi-purpose adhesive bonds dissimilar materials, forming a watertight, weather-resistant seal on joints and boat hardware above and below the waterline.