Time Saver - solderless, crimpless, all you need is just a heat gun to finish the joint, much faster and easier than the old way. Fit for Confined and Narrow Spaces - can be bent after connection and no need to crimp or solder in the confined area, just control the temperature via a heat gun. Better Waterproof and Seal Performance - there is two hot melt waterproof adhesive rings in each butt connector, which help it hold up better to moisture. High Temperature Proof in A Short Time: use exclusive material in the butt connectors to avoid shrink tubing melting before solder ring. IATF16949:2016 Listed: The solder seal connectors meet the newest standard of International Automotive Task Force, which is the most standardized way for you to repair or modify your car. Product Description IP67 Waterproof Solder seal wire connectors come with IP67 water-resistant rating. After being heated, they shrink and water will not be able to go inside, preventing any short circuit issues. Widely used on marine projects. High Success Rate Our wire connectors are upgraded to use exclusive material in the butt connectors to avoid shrink tubing melting before solder ring. The success rate of connecting wire has been greatly improved. Structure Features Polyolefin Tubing Outside and Hot melt Adhesive Inside make connection strong and waterproof.