Heat Shrink Tubing 2:1 Ratio – Wire Cable Sleeve 10mm to 20mm, Multiple Colors

Select a size whose inner diameter (before shrinking) is slightly larger than the cable or connector you need to cover. After applying heat, the tubing shrinks to approximately half its original diameter. For example, 10mm tubing shrinks to typically around 5mm (≈3/16"). When in doubt, size up — you can always apply more heat, but you cannot reverse over-shrinking.

A 2:1 shrink ratio means the tubing will shrink to approximately half its original inner diameter when heat is applied. For example, 20mm tubing (≈0.79" before shrinking) will generally reduce to around 10mm (≈0.39") after heating. This ratio ensures a tight, secure fit around the covered component.

Standard 2:1 polyolefin heat shrink tubing typically activates at around 90°C (194°F) and fully shrinks at approximately 120°C (248°F). A heat gun is the recommended tool. Avoid open flames, which can cause uneven shrinking or scorching of the tubing surface.

Polyolefin heat shrink tubing is generally resistant to moisture, UV exposure, and mild chemicals, making it suitable for many outdoor applications such as marine wiring, garden lighting, and automotive underhood use. However, for prolonged outdoor or submersion applications, we recommend confirming the specific environmental rating with us before ordering.

Yes. The 10mm–20mm size range covers a wide variety of wire bundles, connectors, and cable assemblies. The 10mm size is typically suited for smaller wire bundles or individual thick cables, while 18mm–20mm sizes are generally used for larger harnesses or connector boots. Always verify the pre-shrink inner diameter against your cable's outer diameter before ordering.

Measure the total length of cable or splice you need to cover, then add at least 10–15% extra for overlap and trimming. The 1-meter option is ideal for small repairs or single-use projects. The 5-meter and 10-meter rolls offer better value for ongoing projects, workshop use, or when working on multiple connections of the same size.

This tubing is generally made from polyolefin, a flexible and durable thermoplastic material that provides good electrical insulation, resistance to abrasion, and compatibility with most common solvents and fuels. It is RoHS-compliant in most standard formulations — contact us to confirm compliance documentation if required.