Heat Shrink Tubing 2:1 3:1 4:1 with Glue — Φ1.6mm to Φ65mm Wire Insulation Sleeving

Measure the outer diameter of the wire or connector you need to cover, then select a tubing size that is generally 20–30% larger than that measurement before shrinking. For example, if your wire bundle is 4mm (≈5/32") wide, a Φ6mm tube will typically provide a snug fit after shrinking. This listing covers Φ1.6mm (≈1/16") through Φ65mm (≈2-9/16") — select your size in the variant options above.

The ratio describes how much the tubing shrinks in diameter when heat is applied. A 2:1 ratio shrinks to half its original diameter, 3:1 shrinks to one-third, and 4:1 shrinks to one-quarter. Higher ratios are generally used for irregular shapes, connectors, or applications where a very tight seal is needed. The 3:1 and 4:1 variants on this listing include an inner adhesive lining for added waterproofing and strain relief.

Polyolefin heat shrink tubing typically activates at around 70–90°C (158–194°F) and fully shrinks at approximately 120°C (248°F). A heat gun is the recommended tool for even, controlled shrinking. Avoid open flames, which can cause uneven shrinking, scorching, or damage to the adhesive lining on glue-lined variants.

The 3:1 and 4:1 variants with glue lining are dual-wall tubing that creates a moisture-resistant seal when properly applied, making them suitable for outdoor wiring, marine environments, and automotive use. The standard 2:1 version provides electrical insulation but is not waterproof on its own. For fully exposed outdoor or submersed applications, the glue-lined options are generally recommended.

This listing covers inner diameters from Φ1.6mm (≈1/16") up to Φ65mm (≈2-9/16"), accommodating wire gauges from very fine signal wires up to large power cables and conduit bundles. In most cases, select the size variant that is slightly larger than your cable's outer diameter before shrinking to ensure a tight, secure fit after heat is applied.

Yes. The dual-wall glue-lined 3:1 and 4:1 options are commonly used in automotive harness repair, trailer wiring, and marine electrical connections because the adhesive inner layer bonds to the wire jacket and resists moisture ingress. The polyolefin material is generally resistant to fuels, oils, and UV exposure, making it a practical choice for under-hood and outdoor cable runs.

This product is available in lengths from 1M up to 20M per order. For small repairs or a few connectors, 1M or 2M is typically sufficient. For wiring harness projects, bulk electrical work, or workshop stock, the 10M or 20M rolls offer better value per meter. Select your preferred length in the variant options above.