If you are identifying a replacement piece of adhesive-lined tubing, check its original diameter and colour before relying on the old cable size. Ancor offers 1/2-inch, 3/4-inch and 1-inch tubing that contracts around electrical connections. The part number also identifies the colour and supplied length.
How to recognize the original tubing
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.
The size shown on a package refers to the tubing before heat is applied. A shrunken piece cannot reliably be measured to infer its original part number.
Identify Ancor tubing by MPN and colour
All models below are a single 48-inch (4-foot) length. The AWG values are the manufacturer’s general tubing-selection ranges.
| 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.
Check an electrical connection before replacing its sleeve
Inspect the terminal, crimp and insulation for damage before replacing a sleeve. Measure the largest component the new tubing must slide over, then confirm that the recovered size will seal against the wire 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.
Compare the available Ancor tubing numbers
Choose the MPN to check its current product details and availability.

Ancor 305148
Black single length in the 1/2-inch series; match the installed material before replacing.
Review listing and availability
Ancor 305648
Red 1/2-inch version. It is not a smaller-diameter product because the part number differs.
Review listing and availability
Ancor 306148
Black 3/4-inch single length. Identify it by the nominal tube opening, not its colour alone.
Review listing and availability
Ancor 306648
Red 3/4-inch member of the 306-series; compare against the lug and existing insulation.
Review listing and availability
Ancor 306948
Yellow colour identifies the variant; nominal opening and recovered size match the 306-series.
Review listing and availability
Ancor 307148
Black 1-inch nominal starting diameter; verify clearance over the unshrunk terminal.
Review listing and availability
Ancor 307648
Red one-inch version, supplied as a single 48-inch length rather than a cut-piece pack.
Review listing and availability
Ancor 307948
Yellow one-inch model. Confirm the actual cable or terminal outside diameter before using.
Review listing and availabilityOther marine wire-connection references
Identify Ancor butt connectors · Identify Ancor battery leads
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