1/8 inch heat shrink tubing fits 16–18 AWG wire — the most common gauge range for standard hook-up wire, trailer lighting splices, speaker wire, and e-bike motor controller outputs. ABYC E-11 Table XI rates 18 AWG at 7A and 16 AWG at 10A in a bundled chassis installation; these gauges account for the majority of terminal splice and butt connector work in automotive and marine wiring. At 3.2mm expanded diameter, this tube slides freely over 16 and 18 AWG conductors and recovers to approximately 1.1mm after full heat application. The 3:1 adhesive-lined construction is correct for any connection that may see moisture, vibration, or repeated flexing — the hot-melt liner bonds to the wire jacket and connector barrel, eliminating the gap where corrosion begins. For dry, protected indoor enclosures with no environmental exposure, the 2:1 non-adhesive single-wall is a lower-cost alternative in this size. This size is the industry standard for covering butt splice connectors and ring terminal crimps in automotive door harnesses, trailer wiring repairs, and marine accessory circuits. The 60ft roll covers approximately 144 standard 5-inch connections.
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SKU: B0D645CBP1 · 1/8" (3.2mm) · 60 ft
Complete dual-wall adhesive performance in a bulk roll format. Permanently waterproof, 600V rated, and rated for the harshest environments.
Sizing over a connector? The Wire Gauge row above is for bare conductor. Heat shrink must be sized to the widest point it passes over, so a crimped butt splice or lug barrel needs a larger tube than the wire alone — a 22–18 AWG splice barrel measures 5–6mm, a 16–14 AWG barrel 7–8mm, and a 12–10 AWG barrel 9–11mm. Measure the barrel, allow about 20% clearance, and confirm the recovered diameter is smaller than the narrowest thing the tube must grip. Use the size calculator.
High quality and amazing value for the price
I'll never buy individual bags of heat shrink tubing again. This is very high quality with a shrink ratio that is truly amazing (all of the tubing from this company is). I wonder if I'll be able to use this entire roll in 10 years!
Good quality and sealing heat shrink
Heat shrink works good. Bought this for work. Makes a nice sealed wire connection. Good quality, better than pre cut heat shrink, you can make whatever length you want.
I LIKE THIS!
I solder, and heat shrink, all of my automotive electrical connections. This is a great product, and I can cut it to any length. The price is great, and the shipping was fast!
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1/8 inch (3.2mm) is the 16–18 AWG size — hook-up wire, trailer lighting, nav and instrument runs, speaker and accessory circuits. It is also the size we ship more of than any other, which is the tell: 16 and 18 AWG is where most real wiring work happens, long after the battery cable is done. It expands to 3.2mm, recovers to roughly 1.1mm, and pulls the hot-melt liner down onto the jacket. The one thing worth getting right before you order is what the tube actually has to pass over — the wire, or the crimp on the end of it.
The published pick for 16 and 18 AWG is 1/8", and for bare conductor and terminal tails that is the right answer with clearance to spare — 18 AWG insulated wire runs around 2.0–2.4mm outside diameter and 16 AWG around 2.4–2.8mm, against a 3.2mm mouth. Recovery closes that down to about 1.1mm, so the sleeve grips the jacket rather than resting on it.
What catches people is the crimp. A tube has to clear the fattest point on its way on, and on a small splice that point is the barrel, not the wire. An uninsulated butt barrel on 18 AWG usually passes 1/8" without argument; the same barrel on 16 AWG sits right at the limit, and anything with a nylon or vinyl body on it is well past 3.2mm and needs 3/16" or 1/4". The habit that removes the guesswork is the same one at every size: measure the largest outside diameter the tube must travel over, add 20–30%, and size to that number.
| Covering | ABYC ampacity | Bare wire / tail | Over a crimp |
|---|---|---|---|
| 18 AWG | 7 A | 1/8" — ideal | 1/8" over an uninsulated barrel |
| 16 AWG | 10 A | 1/8" — ideal | Measure the barrel; 3/16" if over 2.5mm |
| 14 AWG | 15 A | Tight — use 3/16" | 3/16" |
| 20–22 AWG | 3–5 A | Loose — use 3/32" | 1/8" |
Expanded ID 3.2mm · recovered ~1.1mm · 3:1 ratio. Ampacity per ABYC E-11 Table XI, conductor bundled outside an engine space. Insulated crimp connectors are not covered by this size.
It is tempting to treat adhesive-lined tubing as a heavy-cable product and put plain sleeve on the thin stuff. The failure data runs the other way. Capillary action does not care about current — salt water wicks along stranded copper under the jacket at 18 AWG exactly as it does at 4/0, and there is far less copper to lose before the circuit goes intermittent. A nav light, a float switch, a transducer lead: none of them draw much, all of them sit in spray, and all of them are miserable to trace once they start reading a volt low.
The liner is what closes the ends. It flows at 120°C into the gap between the cut insulation and the tube, then sets, so there is no open path back down the strands. It also bonds the sleeve to the jacket, which matters more at this gauge than at any other — thin wire flexes, and a sleeve that is only gripping will walk along the wire under vibration until the joint is sitting proud of it.
At 3.2mm there is no way to get the tube on after the crimp without cutting it open. Cut the sleeve, slide it well back down the wire, crimp, then bring it up — the single most common reason a small sleeve ends up taped on instead.
A thin wall recovers fast and the jacket underneath is thin too. Keep the gun moving and stay off the trigger longer than you would on heavy cable — scorching the polyolefin on 18 AWG is easy, and a scorched wall is a cracked wall.
A thin bead of clear adhesive at both ends is the confirmation that the seal closed. On this size the bead is small — look for it rather than expecting it to be obvious.
Run at least 8–10mm onto the jacket each side. On thin wire the joint rarely fails at the crimp; it fails where the stiff sleeve stops and the wire starts bending again.
Sixty continuous feet, cut to length, so nothing is lost to fixed pre-cut pieces. At a 2-inch sleeve over a splice that is roughly 360 sealed joints; at a 5-inch termination with proper overlap, about 144. A full trailer rewire or a panel of instrument runs takes a few feet of it.
That is deliberately more than one job needs. This is the size that gets consumed quietly across a season of small work, and the roll is priced and sized to be the one on the van that you replace when it runs out — not the one you buy per job.
Keep reading →Heat Shrink Size Calculator · Marine Heat Shrink Tubing · How to Waterproof Wire Connections · Size Chart & Selection Guide
Verify the expanded diameter is 20–30% larger than your wire or connector. The tubing must slide freely before heat is applied — if it drags, go one size up.
Cut to length and thread onto the wire or cable before making the splice or crimp. Overlap each terminal or connector end by at least 10mm for a proper seal.
The tubing starts shrinking at 100°C, but the adhesive liner only flows at 120°C — so keep the heat gun moving past the point where it looks shrunk. Start at the center and work outward to push air toward the ends. Adhesive will appear at the tube ends — that is your visual seal indicator.
The tubing should be tight and uniform with adhesive visible at both ends. No gaps, lifting, or cold spots. Pull-test the finished connection to confirm the adhesive bond.
Actual 1/8" tube at full expanded diameter (3.2mm) and after heat recovery. Use this as your fit reference before cutting.
Seals LED strip connections, lamp socket splices, and lighting control wiring exposed to vibration or condensation. 3:1 ratio fits tight spaces.
Protects delicate instrumentation wiring from moisture ingress. Adhesive liner prevents capillary wicking along fine conductors.
Seals trailer connector repairs and small harness splices from road spray, salt, and standing water without special tooling.
Covers solder joints and wire-to-board connections where a watertight, flexible sleeve is required on a confined circuit board.
Used for insulation of thermocouple wire, RTD leads, and signal wiring inside outdoor or wash-down rated enclosures.
Protects under-dash splices, amplifier signal cables, and small connector terminations from moisture and abrasion.
Recovered diameter is approx. 1/3 of the expanded size shown · All sizes ship to USA & Canada
