Red Adhesive-Lined Heat Shrink End Caps 2:1 — Wire Sealing, Multiple Sizes

Each size lists a recommended wire diameter range — for example, the 8×25mm cap fits wire diameters of 5mm–7mm (approximately 3/16"–9/32"). Match your wire's outer diameter including insulation to the "Fit For Wire Dia" range shown in the variant name. When in doubt, size down slightly so the adhesive liner seals tightly around the conductor rather than leaving gaps.

Quick reference examples: 10×30mm fits 6–9mm wire (≈1/4"–3/8"); 25×40mm fits 16–22mm wire (≈5/8"–7/8"); 50×70mm fits 35–45mm wire (≈1-3/8"–1-3/4").

A 2:1 shrink ratio means the cap's inner diameter will shrink to approximately half its original (recovered) size when heat is applied. This ensures a snug mechanical grip on the wire end. The adhesive liner melts simultaneously to create a watertight seal. For most wire end sealing applications, 2:1 is the standard ratio and provides reliable coverage across the listed wire diameter ranges.

Yes. The hot-melt adhesive inner liner flows into gaps and voids as it melts, creating a moisture-resistant seal around the wire end. These caps are generally suitable for outdoor, marine, and automotive environments where moisture ingress is a concern. For fully submerged or high-pressure applications, confirm suitability with your specific installation requirements before use.

Polyolefin heat shrink end caps typically activate at around 70–90°C (158–194°F) and fully shrink at approximately 120°C (248°F). A standard heat gun on a low-to-medium setting works well. Apply heat evenly, starting at the closed end and working toward the open end. Avoid open flames, which can scorch the material unevenly and compromise the adhesive seal.

Yes. These end caps work on stranded wire, solid wire, and small cable bundles. The adhesive liner conforms to irregular surfaces, making them effective for sealing multi-conductor cables and rope-lay conductors. Just ensure the total outer diameter of the bundle falls within the listed wire diameter range for the chosen size variant.

1. Slide the open end of the cap over the wire end so the conductor tip sits near the closed bottom of the cap.
2. Apply heat evenly from the closed end toward the open end using a heat gun.
3. The cap will shrink inward and the adhesive will flow to seal around the wire.
4. Allow to cool for 30–60 seconds before handling or pulling on the wire.

For best results, strip back any excess insulation so the bare conductor does not extend past the cap's closed end.

Regular heat shrink tubing is open at both ends and is used to insulate or bundle wires along their length. A heat shrink end cap is closed at one end, designed specifically to seal and protect the cut or stripped tip of a wire or cable — preventing moisture, corrosion, and short circuits at the termination point. End caps are the correct choice when you need to permanently cap off a wire end rather than sleeve a connection.

The adhesive liner creates a mechanical bond between the cap and the wire insulation, generally providing good resistance to axial pull-out forces in typical wiring applications. Exact pull-out strength varies by wire diameter, surface texture, and heat application quality. For high-vibration or high-tension installations, we recommend securing the wire with an additional cable tie or clamp near the cap. Contact us to confirm specifications for critical load-bearing applications.