Black 2:1 Heat Shrink Tubing 3mm & 4mm — 5 Metre Roll, 600V Rated

Measure the outer diameter of the wire or bundle you need to cover. The tubing should slide over the cable easily before shrinking. As a general rule, choose a size whose pre-shrink inner diameter is at least 20–30% larger than your cable's OD. For single wires, 3mm typically suits AWG 20–24; 4mm generally works for AWG 16–20. When in doubt, size up — you can always add a second layer.

A 2:1 shrink ratio means the tubing will shrink to approximately half its original inner diameter when heat is applied. For example, a 4mm pre-shrink tube will shrink down to roughly 2mm (≈5/64") after heating, conforming snugly around the cable.

Standard polyolefin heat shrink tubing typically activates at around 90°C (194°F) and fully shrinks 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 uneven-shrink the sleeve.

This tubing is made from polyolefin, which is generally moisture-resistant and suitable for light outdoor use. However, it is not adhesive-lined, so it does not form a waterproof seal. For fully weatherproof or submersible applications, consider dual-wall adhesive-lined heat shrink tubing instead.

This tubing is rated at 600V, making it suitable for most residential and light commercial electrical work, automotive wiring, marine connections, and low-voltage electronics. Always verify the voltage requirements of your specific application before use.

Yes. Polyolefin heat shrink tubing is commonly used in automotive and marine wiring for insulating splices, protecting terminals, and bundling cables. It is generally resistant to fuels, oils, and mild chemicals. For saltwater or fully submerged marine use, adhesive-lined tubing is typically recommended for a better seal.

Each order includes a 5 metre (≈16.4 ft) continuous roll in your chosen diameter (3mm or 4mm). Select your preferred size from the variant options above.