Ancor Heat Shrink Butt Connectors feature a heat-activated adhesive built into the sleeve of the heat shrink tubing. When heated to 275° F (135° C), the connector shrinks to form a watertight seal, as well as providing ultimate vibration and strain relief. Each connector is constructed from pure copper for maximum current flow and is tin-plated to resist corrosion from salt and moisture, making it perfect for use in marine environments. A brazed seam ensures maximum strength. UL listed (486C) and CSA recognized.