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2:1 Single Wall — General Purpose Heat Shrink Tubing
9.5mm expanded • ~4.8mm recovered • Fits 6–8 AWG
Size
3/8"
Metric
9.5mm
Roll Length
120 ft
Shrink Ratio
2:1
AWG Fit
6–8 AWG
Important — Not Waterproof
This is single-wall tubing with no adhesive liner. It is moisture-resistant but NOT watertight — not suitable for submersion, direct water exposure, or marine use. For a full waterproof seal, see our 3:1 Dual Wall with adhesive liner.
Technical Data
Wire Compatibility
AWG Range
6–8 AWG
Alternator wires, high-current battery feeds, large fuse holders
Diameter Guide
For best results, choose a size where the expanded diameter is 20–30% larger than the wire or bundle you are covering.
Which Should You Choose
The right product depends on your environment and whether a waterproof seal is required.
| Feature | 2:1 Standard (This Product) | 3:1 Dual Wall |
|---|---|---|
| Waterproof Seal | No — moisture-resistant only | Yes — adhesive liner creates watertight seal |
| Shrink Ratio | 2:1 (shrinks to half diameter) | 3:1 (shrinks to one-third diameter) |
| Roll Length | 120 ft per roll | 20–40 ft per roll (smaller) |
| Cost Per Foot | Lower — best value for volume use | Higher — adhesive liner adds cost |
| Best For | Color coding, bundling, dry indoor insulation | Marine, outdoor, underground, moisture-exposed runs |
Applications — Medium (1/4"–3/8")
Medium sizes cover the most common automotive and workshop wire gauges. The 2:1 single-wall construction is ideal where moisture-resistance is acceptable but a full waterproof seal is not required — shop wiring, household appliance repairs, and bench builds. Large 120 ft rolls make per-foot cost very competitive.
General automotive electrical repairs (interior, non-submerged)
Household appliance wiring repairs and upgrades
Workshop and bench wiring organization and color coding
Solar panel wiring and charge controller connections (dry locations)
Not Suitable For
For these applications, use Helixal 3:1 Dual Wall with adhesive liner.
Product Features
Every roll uses UL listed polyolefin — meets certification requirements for electrical and industrial installations in the USA.
Self-extinguishing formulation passes UL 224 flame testing. Will not propagate flame along a wire run.
High-volume roll with 120 feet of material. Fewer changeovers, lower per-foot cost, and less waste on the bench.
Shrinks to exactly half its supplied diameter — predictable, repeatable results across production runs and field repairs.
Rated from -55°C to +125°C. Stays flexible in cold, does not soften in warm panel environments.
Consistent matte black finish with no bubbles or wrinkles when applied at the correct temperature.
Full Size Range
13 sizes from 3/32" to 2" — all 2:1 single wall, all UL listed.
FAQ
Helixal 3/8" 2:1 Standard is designed for 6–8 AWG. It covers: Alternator wires, high-current battery feeds, large fuse holders. The expanded diameter is 9.5mm; after shrinking it recovers to approximately 4.8mm. For best fit, select a size where the expanded diameter is 20–30% larger than the wire or bundle.
No. This is single-wall tubing with no adhesive liner. It is moisture-resistant — meaning normal humidity and light splashes will not degrade the tubing — but it does not create a watertight seal. For waterproof applications such as marine wiring, underground connections, or outdoor splices exposed to standing water, use Helixal 3:1 Dual Wall which contains a hot-melt adhesive lining.
Each Helixal 3/8" 2:1 Standard roll contains 120 feet of heat shrink tubing. This high-volume roll format keeps per-foot cost low for workshops, production lines, and tradespeople who use a single size repeatedly.
Helixal 2:1 Standard begins to shrink at 90°C (194°F) and achieves full recovery at 120°C (248°F). Use a heat gun for best results — a hair dryer is typically not hot enough. Avoid open flame, which creates uneven heat and can scorch the tubing.
Yes, for dry or interior automotive applications. Dash wiring, interior harness repairs, terminal insulation, and color-coded wire identification are all well suited to 2:1 standard. For engine bay wiring exposed to moisture, or connections near battery terminals in harsh conditions, consider 3:1 Dual Wall with adhesive liner for a more protective seal.
Ready to Order
In stock on Amazon with Prime shipping. Need a different size? Browse all 13 sizes in the Helixal 2:1 Standard range.