A 3:1 ratio means the tubing shrinks to one-third of its original diameter when heat is applied — so this Φ30mm tubing typically recovers to around Φ10mm. For length, measure the section you need to cover and add at least 10–15mm (about 1/2") on each end for overlap. Available lengths: 1M (≈39.4"), 2M (≈78.7"), 5M (≈196.9"), 8M (≈314.9"), and 10M (≈393.7"). Buying a longer roll is generally more economical for ongoing projects.

The supplied inner diameter is Φ30mm (≈1.18"). After full shrinkage at the 3:1 ratio, the recovered inner diameter is typically around Φ10mm (≈0.39"). Recovered wall thickness varies by color batch — contact us to confirm for critical or high-voltage applications.

Yes. The inner adhesive layer melts and flows during shrinkage to create a moisture-resistant seal around cables and connectors, making it generally suitable for outdoor, marine, and automotive environments. For prolonged UV exposure, the black variant typically offers the best UV resistance. Other colors may be used outdoors but may show some UV degradation over extended periods.

Dual-wall adhesive heat shrink tubing of this type typically begins shrinking at around 70–90°C (158–194°F) and fully activates the adhesive at approximately 120–135°C (248–275°F). A heat gun is strongly recommended for even, controlled heat application. Work from the center outward to prevent trapped air. Open flames are generally not advised as they can scorch the outer wall before the adhesive fully activates.

With a supplied inner diameter of Φ30mm (≈1.18"), this tubing is generally suited for cable bundles, conduit ends, or connectors up to approximately 28mm in diameter before shrinkage. It is commonly used on large-gauge battery cables, wiring harnesses, and multi-conductor bundles. Always measure your cable or connector OD before ordering to ensure a proper fit.

Yes. The tubing is supplied in continuous lengths and can be cut to any custom length with scissors or a utility knife before application. Cut ends cleanly and squarely for the best seal. For high-volume or repetitive cuts, a rotary cutter or tube cutter jig can improve consistency.

Color is primarily for identification, organization, or aesthetics and does not generally affect shrink ratio or adhesive performance. Black tubing typically offers the best UV and sunlight resistance for outdoor installations. Other colors — White, Red, Green, Yellow, Blue, Transparent, and Orange — are ideal for color-coded wiring systems in control panels, vehicles, or marine applications.

Standard single-wall heat shrink tubing provides insulation and mechanical protection but does not seal against moisture. Adhesive glue-lined (dual-wall) tubing adds an inner layer of hot-melt adhesive that flows when heated, bonding to the cable jacket and creating a watertight, strain-relieving seal. This makes it the preferred choice for waterproof cable splices, marine wiring, and any application where moisture ingress is a concern.