3M™ Marine Adhesive Sealant is a high-performance Polyurethane Adhesive Sealant that stays flexible and waterproof, yet helps to resist weathering and salt water. A fast curing, one-part polyurethane that chemically reacts with moisture to deliver strong, flexible bonds with excellent adhesion to wood and fibreglass. Forms watertight, weather-resistant seals on joints and boat hardware above and below the waterline. In addition, its flexibility allows for dissipation of stress caused by shock, vibration, swelling or shrinking.