This 400 PCS Heat Shrink Tubing Kit is an ideal tool for various electrical repairs, insulation protection, and industrial applications. Each heat shrink tube features a 3:1 high-efficiency shrink ratio, ensuring a tight fit around various wires and connectors when heated. The dual-wall design includes a premium adhesive lining that melts and bonds securely to the cable surface as the tubing shrinks, forming a sealed waterproof layer that effectively prevents moisture, dust, and other corrosive substances from penetrating. Additionally, these heat shrink tubes exhibit excellent high-temperature resistance and flame retardancy, ensuring they remain stable and safe even in high-temperature environments. Whether you need to repair wires, enhance insulation for cable connections, or provide extra protection for outdoor equipment, this heat shrink tubing kit can meet your needs. It is suitable for a wide range of applications, from automotive and marine repairs to household electrical maintenance. The kit includes 400 pieces of heat shrink tubing in 7 different sizes, with each tube carefully sorted and stored in a durable, portable, and transparent storage case for your convenience and easy access.