Heat Shrink Tubing 3:1 Adhesive Lined — Φ12.7mm Dual-Wall Cable Sleeve

This tubing has a supplied inner diameter of approximately 12.7mm (1/2"). After shrinking at a 3:1 ratio, the recovered inner diameter is typically around 4mm (5/32"). It generally fits cable bundles or connectors in the range of 4mm–12mm before shrinking. Always measure your cable or connector OD and confirm it falls within that range before ordering.

A 3:1 ratio means the tubing shrinks to roughly one-third of its original diameter when heat is applied. Compared to standard 2:1 tubing, this gives you more coverage flexibility — you can use a single size across a wider range of cable diameters. It is especially useful for stepped connectors, terminals, and irregular shapes.

Yes. The dual-wall construction includes an inner adhesive layer that melts and flows during shrinking, creating a moisture-resistant seal around the cable. This makes it generally suitable for outdoor wiring, marine environments, and underground splices where moisture ingress is a concern. For fully submersed or high-pressure water exposure, verify the specific application requirements.

Adhesive-lined dual-wall tubing typically activates at around 70–90°C (158–194°F) and fully shrinks and flows adhesive at approximately 120–135°C (248–275°F). A heat gun is the recommended tool. An open flame (lighter or torch) can be used carefully in the field, but may cause uneven shrinking or scorching. Do not use a standard hair dryer — it generally does not reach sufficient temperature.

This tubing is available in Black, White, Red, Green, Yellow, Blue, and Transparent. Color is purely aesthetic and does not affect electrical or mechanical performance. Transparent is useful when you need to see the underlying wire markings or connector after installation. Black is the most common choice for general electrical work.

Available lengths range from 1M (≈3.3 ft) to 40M (≈131 ft). For small repairs or a handful of splices, 1M–2M is typically sufficient. For automotive wiring harnesses or panel builds, 5M–10M is a common choice. For production runs or large installations, 20M–40M rolls offer better value per meter. Measure your total run length and add at least 10–15% for waste and overlap.

Yes. Adhesive-lined 3:1 heat shrink tubing is widely used in automotive, marine, RV, and off-road vehicle wiring because the inner adhesive creates a strain-relief bond and moisture seal at connectors and splices. It is generally compatible with standard copper wire, tinned copper, and most connector types used in 12V and 24V DC systems.