Marine adhesive-lined heat-shrink tubing insulates and seals properly prepared electrical connections. Unlike an ordinary loose sleeve, the inner adhesive activates with heat to help protect the joint from moisture and provide strain relief. Ancor offers several starting diameters and colours; choosing the right size requires measuring the cable and the widest terminal first.
Start with the unshrunk opening
Nominal 12.7 mm starting diameter; the manufacturer lists recovery to approximately 4 mm.
Nominal 19 mm starting diameter; recovers to approximately 6.4 mm.
Nominal 25.4 mm starting diameter; recovers to approximately 7.9 mm.
These are 3:1 adhesive-lined products: the tubing shrinks to roughly one-third of its initial diameter. The stated size is the unshrunk diameter, not the final recovered diameter.
Ancor adhesive-lined heat-shrink tubing chart
This 48-inch selection comes in black, red and yellow versions. The manufacturer’s AWG ranges are guidelines; the widest lug or splice outside diameter also determines which tubing will fit.
| MPN | Starting diameter | Recovered diameter | Colour | Pack length | Manufacturer wire range |
|---|---|---|---|---|---|
| 305148 | 1/2 in | 5/32 in | Black | 1 × 48 in | 8–4 AWG reference |
| 305648 | 1/2 in | 5/32 in | Red | 1 × 48 in | 8–4 AWG reference |
| 306148 | 3/4 in | 1/4 in | Black | 1 × 48 in | 8–2/0 AWG reference |
| 306648 | 3/4 in | 1/4 in | Red | 1 × 48 in | 8–2/0 AWG reference |
| 306948 | 3/4 in | 1/4 in | Yellow | 1 × 48 in | 8–2/0 AWG reference |
| 307148 | 1 in | 5/16 in | Black | 1 × 48 in | 2–4/0 AWG reference |
| 307648 | 1 in | 5/16 in | Red | 1 × 48 in | 2–4/0 AWG reference |
| 307948 | 1 in | 5/16 in | Yellow | 1 × 48 in | 2–4/0 AWG reference |
Manufacturer specifications: cross-linked polyolefin, adhesive lining, 3:1 shrink ratio, activation at 125°C (257°F), operating range −40°C to 110°C.
Fitting and recovering adhesive-lined tubing
Measure both the cable insulation and the widest point of the crimp or lug. Select tubing that slides over the joint before heating but recovers firmly onto the cable, with enough length to cover the exposed connection and overlap intact insulation.
A cable termination may be wider than its wire insulation. Check the actual assembly and follow the manufacturer’s heat-tool instructions, applying heat evenly without damaging the cable or adjacent components.
Ancor heat-shrink tubing by diameter and colour
Open the matching product for its current details and availability.

Ancor 305148
Black 1/2-inch tubing for sealing suitable finished cable terminations.
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Ancor 305648
Red version of the 1/2-inch nominal diameter, supplied as one 48-inch piece.
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Ancor 306148
Black 3/4-inch tubing to cover larger cable connections after checking their outside dimensions.
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Ancor 306648
Red 3/4-inch tubing; the manufacturer lists recovery to approximately 1/4 inch.
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Ancor 306948
Yellow 3/4-inch tubing in the same dimensional family as 306148 and 306648.
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Ancor 307148
Black one-inch tubing for larger cable and lug barrels within the manufacturer’s sizing guidance.
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Ancor 307648
Red one-inch tubing with 3:1 recovery characteristics for suitable electrical assemblies.
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Ancor 307948
Yellow one-inch adhesive-lined tubing for the manufacturer’s larger cable-size range.
See product details and availabilityMore marine electrical parts guides
Ancor heat-shrink butt connectors · Marine battery cable assemblies
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