It is made of transparent polyolefin, and the size used is easy to indentify by colored hot melt adhesive rings. The material of solder sleeve has good melting speed and soldering effect, providing the most convenient operation. Designs of this product is heat shrink tube protection for the outer layer of wires, the tin ring welding to the cables, and the sealing of hot melt adhesive rings on the ends of heat shrink tube. All operations can be completed in one heating step, and the simple construction method can reduce the installation cost.