Black Heat Shrink Tubing φ1–φ25mm | Electrical Wire Insulation Sleeve for Automotive & DIY

Measure the outer diameter of your wire or connector before shrinking. The tubing's inner diameter should be at least 10–20% larger than the wire OD so it slides on easily. After heat is applied, it will typically shrink to roughly half its original diameter, creating a snug, secure fit. For example, if your wire is φ4mm, choose the φ6mm or φ8mm tube. When in doubt, size up — you can always apply more heat, but you cannot un-shrink the tubing.

This heat shrink tubing generally has a 2:1 shrink ratio, meaning it shrinks to approximately half its listed (expanded) diameter when heat is applied. So a φ10mm tube will recover to roughly φ5mm. Always verify the final recovered diameter against your component size before ordering in bulk.

A standard heat gun set to around 90–120°C (194–248°F) is the recommended tool. Move the heat gun slowly and evenly along the tubing to avoid hot spots. In a pinch, a lighter or match can work for small diameters, but a heat gun gives the most consistent, professional result — especially for larger diameters like φ16mm–φ25mm.

Yes. The black color provides better UV resistance compared to clear tubing, making it generally suitable for automotive wiring harnesses and outdoor low-voltage electrical connections. For harsh marine environments or direct-burial applications, we recommend confirming the specific material rating with us before purchase.

This tubing is typically rated for low-voltage applications up to 600V. It is well-suited for automotive 12V/24V systems, household appliance cord repairs, and general DIY electrical projects. For high-voltage industrial applications, please contact us to confirm suitability before ordering.

For a single wire splice or connector repair, 1 Pcs is usually sufficient. For wiring harness projects or workshop stock, the 10 Pcs or 20 Pcs packs offer better value per piece. We recommend ordering a mix of sizes — for example, φ3mm, φ6mm, and φ10mm — to cover the most common wire gauges in automotive and DIY work.

Yes. Heat shrink tubing works equally well on stranded copper wire, solid core wire, and over connectors, crimp terminals, butt splices, and solder joints. The key is matching the pre-shrink (expanded) diameter to the component you are covering — the tubing should slide over the component with a little room to spare before you apply heat.