6.4mm Heat Shrink Tubing – Waterproof Electrical Sleeving, 8 Colors

6.4mm (approximately 1/4" or 0.25") is the inner diameter before shrinking. This tubing typically shrinks to about half its original diameter (2:1 ratio), ending up around 3.2mm after heat is applied. For a secure fit, choose tubing whose pre-shrink ID is slightly larger than your wire or bundle — generally 10–20% larger works well. For example, a 5mm wire bundle fits comfortably inside 6.4mm tubing.

Measure the total length of wire or splice you need to cover, then add a small overlap on each end — typically 5–10mm (about 1/4") per side. For single wire repairs or small DIY jobs, 1m or 2m is usually sufficient. For automotive wiring harnesses, marine installations, or larger projects, the 5m or 10m options offer better value per meter.

This heat shrink tubing generally operates at a 2:1 shrink ratio, meaning it shrinks to approximately half its original inner diameter when heat is applied. Starting at φ6.4mm, it will typically shrink down to around 3.2mm. This makes it suitable for wires and connectors in the 3–6mm range. If you need a tighter or looser fit, contact us to confirm the exact ratio for your variant.

Yes. This tubing is designed to provide a waterproof, moisture-resistant seal when properly applied with a heat gun. It is suitable for outdoor wiring, marine cable connections, and automotive use where exposure to rain or humidity is a concern. For fully submersed or high-pressure water environments, we recommend confirming the specific IP rating with us before purchase.

Polyolefin heat shrink tubing typically begins to activate at around 90°C (194°F) and fully shrinks at approximately 120°C (248°F). A standard heat gun is the recommended tool — most heat guns with a low setting work well. Avoid using open flames (lighters, torches) where possible, as uneven heat can cause bubbling, uneven shrinkage, or scorching.

Yes, 6.4mm heat shrink tubing is commonly used for automotive wire splices, connector insulation, and wiring harness protection. It generally withstands the temperature ranges found in under-dash and cabin environments. For high-heat zones such as near the engine block or exhaust, we recommend verifying the rated operating temperature before use — contact us to confirm.

No — all color variants share the same polyolefin material and performance characteristics. Color is purely for identification purposes. Color-coding is especially useful in multi-wire installations, electrical panels, or automotive harnesses where distinguishing circuits at a glance saves time and reduces errors.