Purple 2:1 Heat Shrink Tubing — φ1mm to φ50mm, 1m / 5m / 10m Lengths

Measure the outer diameter of the wire, connector, or bundle you need to cover. Choose a heat shrink tube whose expanded (pre-shrink) inner diameter is at least 10–20% larger than that measurement. For example, if your wire bundle is 4mm (≈5/32") across, a φ5mm or φ6mm tube typically gives a comfortable fit before shrinking. With a 2:1 shrink ratio, the tube will shrink down to roughly half its listed diameter when heat is applied.

A 2:1 ratio means the tubing will shrink to approximately half its original inner diameter when heated. For example, a φ10mm (≈3/8") tube will shrink down to roughly φ5mm (≈3/16"). This ratio is generally sufficient for most wire insulation, splicing, and bundling tasks without requiring excessive heat.

Standard polyolefin heat shrink tubing is typically rated for indoor and protected outdoor use. It provides good resistance to moisture, mild chemicals, and UV exposure in most conditions. For harsh outdoor, marine, or fully waterproof applications, a dual-wall adhesive-lined heat shrink tube is generally recommended for a sealed connection.

Polyolefin 2:1 heat shrink tubing typically begins to shrink at around 70–90°C (158–194°F) and achieves full shrinkage at approximately 120°C (248°F). A heat gun set to low or medium is the recommended tool — move it steadily along the tube to shrink evenly. Avoid open flames, which can scorch or cause uneven shrinkage.

Yes. Polyolefin heat shrink tubing is widely used in automotive wiring repairs, connector insulation, and harness bundling. It is generally resistant to engine-bay fluids such as oil and coolant splatter. Confirm the operating temperature range matches your specific application — particularly if the tubing will be placed near exhaust components or other high-heat areas.

Use sharp scissors or a utility knife for a clean, straight cut. Cut the tubing slightly longer than the area you need to cover — typically add 5–10mm on each end — because the tubing will also shrink slightly in length (longitudinal shrinkage is usually around 5–10%) when heat is applied. Polyolefin does not fray when cut cleanly.

Standard polyolefin 2:1 heat shrink tubing is typically rated for up to 600V, which covers most low-voltage electrical wiring, automotive 12V/24V systems, and hobby electronics. For household branch circuit wiring, always follow local electrical codes and confirm the tubing's rating meets your jurisdiction's requirements before use.