2:1 Ratio Heat Shrink Tubing — 12 Colors, 1mm–210mm Diameter, 1m/2m/5m

Measure the outer diameter of the wire or connector you need to cover, then select a tubing size that is at least 10–20% larger before shrinking. With a 2:1 shrink ratio, the tubing will shrink to approximately half its listed diameter. For example, 10mm tubing will shrink to roughly 5mm (≈3/16"). When in doubt, size up — you can always apply more heat to tighten the fit.

A 2:1 shrink ratio means the tubing will shrink to approximately half its original inner diameter when heat is applied. For example, a 22mm (≈7/8") tube will shrink down to roughly 11mm (≈7/16"). This ratio is generally suitable for most standard wire bundling, insulation, and strain relief applications.

This heat shrink tubing typically activates at around 70–90°C (158–194°F) and fully shrinks at approximately 120°C (248°F). A heat gun is recommended for even, controlled shrinkage. A lighter or match can work for small diameters in a pinch, but a heat gun gives more consistent results and reduces the risk of scorching.

This tubing is generally made from flame-retardant polyolefin material, which resists ignition and self-extinguishes. It is typically rated for use in temperatures from approximately -55°C to +125°C (-67°F to +257°F). For outdoor or marine applications, it provides basic moisture resistance, though for fully waterproof connections a dual-wall adhesive-lined variant is generally recommended.

This tubing is compatible with a wide range of wire gauges and connector types. The available diameters (1mm–210mm) cover everything from thin signal wires to large cable bundles and conduit. It works with standard butt connectors, ring terminals, spade connectors, and multi-wire harnesses. Always verify the pre-shrink diameter fits loosely over your connector before applying heat.

Color choice is typically based on wiring convention or personal preference. Black is the most common for general-purpose use. Red is often used for positive leads, while black is used for negative/ground. Yellow-green is the standard color for earth/ground wires in many electrical codes. Clear tubing lets you see the wire or label underneath. Other colors (blue, green, white, etc.) are useful for color-coding multi-wire harnesses.

Yes, polyolefin heat shrink tubing is generally well-suited for automotive wiring repairs, including splices, connector insulation, and harness protection. It typically withstands the temperature ranges found in engine bays and under-dash environments. For connections exposed to fuel, oil, or constant moisture, a dual-wall adhesive-lined version is generally preferred for a fully sealed result.