Package contents: 4 times shrink heat shrinkable tubing 190 pieces. 【4:1 shrinkage】Returns to 1/4 of its original diameter and forms a tight seal. Highest thermal shrinkage on the market. and form a tight seal. Eliminates the problem of 2:1 tubes not shrinking tightly enough. Internal glue: When heated, the internal adhesive flows out and seals the connection, resulting in waterproof and long-lasting insulation. 【Multiple Sizes】We include 5 of the most commonly used diameters, ranging from 1/8 inch to 3/4 inch. We include larger diameter heat shrink tubing, which is pre-cut to 1.75 inches Easy to use: Simply slide the heat shrink tubing through the connection point and heat up. Make a professional connection in seconds. They are perfectly insulated and sealed. They form a protective, antiseptic, and decorative layer.