Heat Shrink Tubing Kit: There are heat shrink tubing in the transparent box.Inner diameters included in delivery: 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 5 mm, 6 mm, 8 mm, 10 mm. Several Colors: Yellow, blue, black, green, red.Different colored heat shrink tubing making it easy to match tubing.Retraction Ratio: 2:1 (will retract to 1/2 of its supplied diameter). Harmless to Health: The material composition of the heat shrink tubing set does not contain materials such as PBBE, PBBO, PBB, etc.does not produce harmful gases.Effective for insulating or protecting cables in industry or at home, also useful for repairing damaged sheath. Easy to Use: Simply slide the heat shrink tubing over the desired connection point and then heat it.This means you can make professional connections in seconds and extremely easily. Wide Usage: It is mainly used in cable connections, corrosion and rust protection of solder joints, protection and insulation of electronic components of line segment and wire harness.With effect for insulating or protecting cables throughout the house or in industry: machine, garden, electronics, car, etc.