Measure the total length of wire or cable you need to cover, then add at least 10–15% extra for overlap and trimming. For a single wire repair, 1 metre is typically sufficient. For wiring harnesses or automotive projects, 10–50 metres is generally recommended to have enough on hand. Buying a longer spool is usually more economical per metre than multiple short lengths.

A 2:1 ratio means the tubing shrinks to half its original (unshrunk) diameter when heat is applied. This 1mm tubing starts at φ1mm unshrunk and shrinks to approximately 0.5mm, creating a snug, secure fit around the wire or component. The shrinkage is primarily radial (diameter), with minimal lengthwise change — typically less than 5–10%.

Standard polyolefin heat shrink tubing generally provides good resistance to moisture, UV exposure, and mild chemicals, making it suitable for many outdoor and automotive wiring applications. For harsh marine environments or extreme weather exposure, a dual-wall adhesive-lined heat shrink variant is typically recommended for added waterproof sealing. This single-wall tubing is well-suited for interior automotive wiring harness repairs and under-dash cable management.

Polyolefin heat shrink tubing generally begins to shrink at around 70–90°C (158–194°F) and fully recovers at approximately 120°C (248°F). A heat gun set to low or medium is the recommended tool for even, controlled shrinkage. Open flames such as lighters or matches can cause uneven shrinkage, scorching, or damage to the wire insulation underneath, so they are generally not recommended for precision work.

The φ1mm unshrunk inner diameter is designed for very fine wires, typically in the AWG 30–26 range or equivalent metric gauges. It is commonly used for individual wire strands, LED leads, small electronic component leads, thermocouple wires, and model/RC wiring. Always measure your wire's outer diameter (including its existing insulation) and confirm it is smaller than 1mm before ordering. If your wire is thicker, please check our larger diameter heat shrink tubing options.

Colored heat shrink tubing allows for easy color-coded wire identification, which is especially useful in automotive wiring, electronics projects, and multi-wire harnesses where tracing individual wires is important. Red is commonly used for positive leads, black for negative or ground, and other colors for signal or auxiliary wires. Clear tubing lets you see the wire or label underneath, which is useful for inspection or labeling purposes. Black remains the most common choice for general insulation and offers the best UV resistance among the available colors.

Polyolefin heat shrink tubing typically experiences minimal longitudinal (lengthwise) shrinkage — generally less than 5–10% in length. The primary shrinkage is radial (diameter reduction). To be safe, always cut your tubing slightly longer than the area you need to cover, and apply heat gradually from one end to the other to ensure even shrinkage without bunching.