Green Heat Shrink Tubing – 2:1 & 3:1 Ratio, Φ0.6mm–Φ80mm, Wire & Cable Electrical Sleeving

Measure the outer diameter of the wire or connector you need to cover, then choose a tubing size whose recovered (shrunk) diameter is slightly smaller than that measurement. For a 2:1 tube, the recovered diameter is typically half the supplied diameter. For example, a Φ6mm tube recovers to approximately Φ3mm (≈0.12"). When in doubt, size up one step to allow easy insertion before shrinking.

A 2:1 ratio means the tubing shrinks to half its original diameter when heated — ideal for standard wire insulation and bundling. A 3:1 ratio with adhesive lining shrinks to one-third its original diameter and the inner adhesive melts to create a waterproof, strain-relieved seal — generally preferred for outdoor connections, marine wiring, and any application requiring moisture protection.

Polyolefin heat shrink tubing typically activates at around 90°C (194°F) and fully recovers at approximately 120°C (248°F). A heat gun set to low or medium is generally sufficient. Avoid applying an open flame directly to the tubing, as this can cause uneven shrinkage or surface scorching.

The 2:1 ratio (without adhesive) provides basic insulation and is suitable for dry indoor applications. For outdoor, marine, or high-moisture environments, the 3:1 ratio with adhesive lining is recommended — the melted adhesive creates a watertight seal around the connection, making it a reliable choice for marine cable sleeving and automotive wiring harness repair.

The size range of Φ0.6mm to Φ80mm covers a very wide range of wire gauges and cable bundles — from fine signal wires (typically AWG 30–28 at the small end) to large power cables and conduit bundles at the larger sizes. Select the variant whose supplied diameter is larger than your wire's outer diameter to allow easy insertion before shrinking.

This tubing is made from polyolefin, which is generally flame-retardant and meets common electrical safety standards. Polyolefin heat shrink is typically RoHS compliant and halogen-free. For specific compliance documentation required for a regulated project, please contact us to confirm.

Standard scissors or a sharp utility knife work well for cutting polyolefin heat shrink tubing. Cut the tubing slightly longer than the area you need to cover — typically 5–10mm (≈0.2"–0.4") of overlap on each side — to account for any longitudinal shrinkage that occurs during heating.