3:1 Heat Shrink Tubing Without Adhesive — Φ1.5mm to Φ6mm, 6 Colors

Measure the outer diameter of the wire or connector you need to cover, then select a tubing size whose recovered (shrunken) diameter is slightly smaller than that measurement. For example, Φ1.5mm tubing typically recovers to about 0.5mm, while Φ6mm tubing recovers to about 2mm. When in doubt, size up — you can always apply more heat to achieve a tighter fit. If you're working in inches: 1mm ≈ 0.039", so Φ3mm expanded ≈ 0.12" and Φ6mm expanded ≈ 0.24".

A 3:1 shrink ratio means the tubing will shrink to approximately one-third of its original diameter when heat is applied. This gives you more flexibility to cover irregular shapes, connectors, or bundled cables compared to standard 2:1 tubing — making it a better choice for automotive connectors, terminal ends, and multi-wire bundles.

This tubing is made from polyolefin, which generally offers good resistance to UV exposure and moisture. However, since it does not have an adhesive inner lining, it is not fully waterproof. For outdoor or marine applications requiring a watertight seal, we recommend using adhesive-lined (dual-wall) heat shrink tubing instead. For sheltered outdoor use — such as under a hood or inside an enclosure — this single-wall tubing is generally suitable.

Polyolefin heat shrink tubing typically begins to shrink at around 90°C (194°F) and fully recovers at approximately 120°C (248°F). A heat gun set to low or medium is the recommended tool. Avoid open flames, which can scorch or unevenly shrink the tubing. Keep the heat gun moving in a slow, sweeping motion from the center outward for the most uniform result.

Yes. The available diameters (Φ1.5mm through Φ6mm) generally cover a wide range of AWG wire sizes. Φ1.5mm is typically suited for very fine wires (around 26–30 AWG), while Φ6mm can accommodate heavier gauge wires or small connector housings. Always verify by measuring your wire's outer diameter before ordering, as insulation thickness varies by wire type and manufacturer.

Color-coded heat shrink tubing makes it easy to organize and identify wiring in complex harnesses, automotive builds, or electronics projects. Using red for positive, black for negative, and other colors for signal or ground lines is a common industry practice that reduces wiring errors during assembly and speeds up troubleshooting during maintenance. It's especially useful in multi-wire cable management projects.

Use sharp scissors or a utility knife for clean cuts. Cut the tubing slightly longer than the area you need to cover — generally add 5–10mm (about 1/4") on each end to account for any slight shrinkage along the length axis during heat application. For precision cuts on small diameters like Φ1.5mm, a sharp hobby knife gives the cleanest edge.