Black Heat Shrink Tubing 2:1 — Electrical Wire Sleeve, Round & Flat Tube, φ0.6mm–φ180mm

Measure the outer diameter of your wire or connector before shrinking. With a 2:1 shrink ratio, the tubing should slide over the wire easily before heat is applied — choose a size where the pre-shrink inner diameter is typically 20–30% larger than your wire's OD. For example, a φ4mm tube generally suits wires around 2–3mm in diameter. When in doubt, size up rather than down.

A 2:1 shrink ratio means the tubing will shrink to approximately half its original inner diameter when heat is applied. So a φ10mm tube will shrink down to roughly φ5mm. This is the most common ratio for general electrical insulation, wire bundling, and connector protection.

This tubing generally begins to shrink at around 90°C (194°F), with full shrinkage typically achieved at 120°C (248°F). A heat gun set to low or medium is the recommended tool for even, controlled application. Avoid holding a flame too close for extended periods, as this can scorch the tubing surface.

Polyolefin heat shrink tubing generally offers good resistance to moisture, UV exposure, and mild chemicals, making it suitable for most outdoor and semi-exposed wiring applications. For fully submerged installations or prolonged UV exposure, an adhesive-lined (3:1) variant is typically recommended for a watertight seal.

Round tube maintains a circular cross-section and is ready to slide over wires straight from the roll. Flat tube is supplied in a flattened form, which makes it easier to store, cut, and handle in bulk — it expands to a round profile when heat is applied. Both options perform identically once shrunk onto a wire or connector.

Yes. Polyolefin heat shrink tubing is widely used in automotive wiring harnesses, connector insulation, terminal protection, and sensor wire repair. It is generally resistant to engine fluids, vibration, and the temperature fluctuations common in vehicle environments. For high-heat zones near exhaust components, confirm the operating temperature range for your specific diameter before use.

For small repairs or prototyping, a 2M or 5M roll is typically sufficient. For larger wiring harness builds, control panel work, or production runs, 10M, 20M, or 50M rolls offer better value per meter. As a general rule, order slightly more than your measured need to account for trimming and test cuts — heat shrink cannot be un-shrunk once applied.