Heat shrink tubes are usually made from materials like polyolefin or PVC. Polyolefin is more commonly used because it has good electrical insulation properties and is flexible.
The shrink ratio is typically 2:1 or 3:1, meaning the tube shrinks to 50% or 33% of its original diameter when heated.
 These tubes are used to insulate wires, protect connections, provide strain relief, and protect against abrasion and chemicals. They are commonly used in electronics, automotive, electrical, and DIY projects.
The kit contains 328 pieces of heat shrink tubing in various sizes and often in a range of colors. The variety of sizes allows for flexibility in use, catering to different wire diameters.
Sizes may range from small tubes for tiny wires (e.g., 1mm or 2mm diameter) to larger tubes for thicker cables (e.g., 10mm or 12mm diameter).
The kit often comes with multiple colors such as red, black, blue, yellow, green, white, etc. Color coding helps identify different circuits or wires, which can be useful for organization and troubleshooting in electrical projects.