3:1 Yellow Adhesive Heat Shrink Tubing – Glue Lined Waterproof Sleeving

Measure the outer diameter of your wire bundle before shrinking. With a 3:1 shrink ratio, the tubing should start at roughly 3 times the final diameter you need. For example, if your bundle measures 4mm after insulation, choose the φ12.7mm size. When in doubt, size up — you can always shrink tighter, but you cannot expand tubing that is too small.

This tubing uses a 3:1 shrink ratio, meaning it shrinks to approximately one-third of its original inner diameter when heat is applied. This is generally more than double the coverage of standard 2:1 tubing, making it suitable for irregular shapes, stepped connectors, and situations where a tight, conforming seal is required.

Yes. The inner wall is lined with a thermoplastic adhesive (hot-melt glue) that melts and flows during shrinking to create a moisture-resistant seal around the wire or connector. This makes it suitable for outdoor, marine, and automotive applications where moisture ingress is a concern. For full submersion applications, confirm suitability with your specific use case.

Yes. The adhesive glue lining provides a seal that resists moisture, dust, and mild chemical exposure. It is generally suitable for outdoor wiring, marine boat wiring, and automotive underhood use. For prolonged saltwater submersion or extreme chemical environments, confirm the specific operating conditions against your application requirements.

Typically, a heat gun set to around 90–120°C (194–248°F) is sufficient to begin shrinking. Full adhesive activation generally occurs at around 120°C (248°F). Avoid open flames, which can scorch the tubing unevenly. A heat gun with a concentrator nozzle gives the most consistent results, especially on smaller diameters.

Standard 2:1 tubing shrinks to half its original diameter and typically has no adhesive lining. This 3:1 glue-lined tubing shrinks to one-third its original diameter and includes an inner adhesive layer that bonds to the substrate, providing a waterproof, strain-relieved seal. It is the better choice for connectors, splices, and any outdoor or marine wiring where a plain sleeve would not provide adequate protection.

The yellow polyolefin outer jacket is generally resistant to moderate UV exposure. For extended direct sunlight applications, additional UV protection or conduit is recommended. The yellow color also serves as a practical visual identifier in wiring harnesses where color-coding is used to distinguish circuits.