Measure the outer diameter of your cable bundle or pipe. Choose a heat shrink size where the expanded inner diameter (φ) is at least 10–20% larger than your bundle's widest point. With a 2:1 shrink ratio, the tubing will shrink to approximately half its listed diameter after heat is applied. For example, φ100mm (≈3.9") tubing will shrink down to approximately φ50mm (≈2"). When in doubt, size up — a slightly oversized tube will still shrink down tightly.

This large bore heat shrink tubing has a 2:1 shrink ratio, meaning it shrinks to approximately half its original expanded diameter when heat is applied evenly with a heat gun. The listed diameter (φ) is the pre-shrink expanded size. Always account for this ratio when selecting the correct size for your application.

This tubing is generally suitable for light outdoor use, providing moisture resistance and protection for cable bundles and pipe joints. The Black variant typically offers better UV resistance for prolonged outdoor exposure. For long-term outdoor, direct burial, or submersion applications, additional weatherproofing measures are generally recommended. Contact us to confirm suitability for your specific outdoor environment.

A heat gun is strongly recommended for large diameter heat shrink tubing. Apply heat evenly in a slow, sweeping motion along the length of the tubing, working from the center outward to avoid trapping air bubbles. Open flames such as lighters or torches are not recommended for large bore sizes as they can cause uneven shrinkage, scorching, or surface damage. A heat gun with adjustable temperature settings gives the best control.

The Black variant provides full coverage and generally better UV resistance, making it ideal for outdoor cable management, automotive underhood wiring, and applications where a clean, finished appearance is needed. The Transparent variant allows you to see the underlying cable markings, color codes, labels, or connections through the tubing after installation, which is useful for inspection, troubleshooting, and identification in control panels or junction boxes.

This large bore heat shrink tubing is typically used for bundling and insulating large cable harnesses in marine, automotive, and industrial settings; covering and sealing pipe joints and conduit terminations; providing strain relief on heavy-duty electrical splices; and protecting wire bundle ends from moisture and abrasion. It is generally suitable for any application where standard heat shrink sizes are too small to cover the bundle or fitting.

Each listing provides 1 meter (≈39.4") of tubing. For most cable end-sealing or joint-covering applications, 100–300mm (4"–12") of tubing per joint is typically sufficient. For longer runs or full cable harness coverage, calculate the total length needed before ordering. Adding 10–15% extra is generally recommended to account for trimming, positioning, and any re-application if needed.