Nice product at great price
Was wiring my car and had quite a few smaller wires to crimp and cover. This worked great — shrinks clean and consistent every time.
Church's · Verified Purchase★ Verified
2:1 Single Wall · UL 224 Recognized
1"
2:1 Heat Shrink
Fits300–400 MCM25.4mm
1 inch heat shrink tubing fits 300 to 400 MCM conductors and large cable assemblies — used for protecting large wire bundles, sealing cable entries at panel knockouts, conduit termination finishing, and covering industrial wiring terminations at switchgear and motor control centers. At 25.4mm expanded diameter, this tube slides freely over 300–400 MCM conductors and large bundles and recovers to approximately 12.7mm. The 2:1 single-wall construction, qualified to UL 224, is the standard specification for mechanical protection, abrasion resistance, and bundle identification in dry industrial environments — cable trays, MCC panels, and distribution switchgear in climate-controlled facilities. When the cable penetration must be sealed against water ingress at an outdoor enclosure or weatherproof panel, the 3:1 dual-wall with adhesive liner is the correct specification. The 90ft roll provides practical job-site quantity for plant maintenance electricians, cable assembly operations, and industrial contractors where 1" tubing is used across multiple termination points on the same project.
★★★★★4.7 · 225 verified ratings across the Helixal range
17 in stock · Ships in 24h
Order up to 17 online · need more? Trade pricing
Size1" · 25.4mm
Click any size to navigate · 90 ft per roll
$35.9990 ft spool
→ Dispatched within 24 hours — delivered in 1–3 days→ 30-day money-back guarantee — 30 days to return it
Qty
1
Secured by Stripe · No account needed
→Ships USA & Canada
→ISO 9001
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SKU: B0FJHQJ9SZ · 1" (25.4mm) · 90 ft
Spec Sheet
1"
data sheet.
High-volume UL 224 Recognized polyolefin at an honest per-foot cost. The industry standard for band marking, bundling, and dry indoor electrical insulation.
Imperial Size
1"
Expanded diameter
Metric Size
25.4mm
Nominal
Roll Length
90 ft
Per spool
Wire Gauge
300–400 MCM
Bare conductor
Shrink Ratio
2:1
Single wall
Construction
Single Wall
No adhesive liner
Adhesive Liner
None
Not waterproof
Voltage Rating
600V AC
UL 224 — 600 V rms
Temp Rating
-55°C to +125°C
Continuous service
Shrink Temp
100°C (212°F)
Shrinking starts
Material
Polyolefin
UL 224 Recognized
Certification
UL 224
Recognized Component
Flammability
Self-extinguishing
UL 224 Recognized
Color
Black
Standard finish
Moisture
Resistant — not sealed
Single wall only
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.
What the
trade says.
Verified Buyers ★ · Full Range4.7★★★★★225 ratings · 84% 5-starCombined verified-buyer rating for every Helixal product — all ratios, all sizes — not this size alone.
Perfect for bulk workshop use
Bought this for my automotive workshop and the 120ft roll is exactly what I needed. Shrinks consistently and cleanly every time. Much better value than small packs.
Mike R. · Verified Purchase★ Verified
Professional finish every time
Clean black finish, no bubbles or wrinkles when applied correctly. UL listing is important for commercial electrical work — ticks that box too.
James T. · Verified Purchase★ Verified
Customer Reviews
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Sizing & Application — 1 inch, 90ft roll
Covering a bundle and sealing a bundle are different verbs.
1 inch (25.4mm) recovers to about 12.7mm. It fits 300–400 MCM conductors, large multi-wire bundles and the lug barrels used on 4/0 AWG — cable trays, MCC panels, distribution switchgear. It covers a bundle well and it does not seal one, and the distinction is worth being precise about because at this diameter the two applications look identical from outside.
What happens inside a shrunk tube over three conductors
Lay three conductors together and the cross-section is a rounded triangle with deep grooves where the circles meet. A recovering tube follows the outer envelope of that shape: it touches the three high points, spans the grooves between them, and stops when it can shrink no further against the conductors.
What remains is three continuous channels running the length of the tube. They are invisible from outside, the finish looks tidy, and if the tube was only ever meant to bundle and identify, none of that matters. Abrasion protection, mechanical restraint and colour identification are all delivered exactly as intended.
It matters when the tube is being asked to keep water out. Those channels connect one end to the other, so water entering at the wet end travels the full length and emerges wherever the bundle opens out — often inside the enclosure the penetration was meant to protect. The tube has not failed; it was doing the job it is built for, in an application that needed a different one.
1 inch on the 90ft roll
| Property | Figure | Why it matters |
|---|---|---|
| Expanded diameter | 25.4mm (1") | Passes over 300–400 MCM and 4/0 lug barrels |
| Recovered diameter | ≈12.7mm | The 2:1 ratio halves; a narrower bundle range than 3:1 |
| Typical bundle OD | Up to ≈20mm | Measure at the fattest point, including tape or lacing |
| Does well | Bundling, abrasion, identification | Dry cable trays, MCC panels, switchgear |
| Does not do | Sealing a bundle | Grooves between conductors stay open end to end |
| Roll length | 90 ft | A few 6–8 in pieces per job — genuine facility stock |
On a single round conductor a 2:1 tube conforms fully. The groove problem is specific to bundles and to stepped assemblies.
When to use the dual-wall instead
01 · The penetration is outdoors or wet-rated
The 1" 3:1 Dual Wall carries a hot-melt liner that flows at 120°C and is pressed into the grooves until the cross-section is solid. That is the sealing product.
02 · The bundle is over about 20mm
Clearance disappears fast at this scale. Step to 1-1/4 inch, which clears roughly 25mm.
03 · Medium-voltage splice work
Heavy-wall cable splice tubing is a separate class with its own qualification. Do not substitute general-purpose tubing into a splice kit specification.
04 · Above 600V
600V rms. On a 1000V marine DC bus the conductor insulation carries the rating and tubing is a cover over an already-rated component.
Keep reading →1" 3:1 Dual Wall — the sealing version · Dual Wall vs Single Wall Heat Shrink · Heat Shrink Tubing: The Complete Guide
How it shrinks.
01
Measure & Select
Choose a size where the expanded diameter is 20–30% larger than your wire or bundle. Smaller tubes will slide on easier; slightly oversize is better than too tight.
02
Cut & Thread
Cut to length and thread onto the wire before making the splice. The tubing cannot pass over a crimped terminal — position it first, then complete the connection.
03
Apply Heat
The tubing starts shrinking at 100°C — use a heat gun and keep it moving until it has shrunk evenly along its length. Work from the center outward. Avoid open flame — it scorches the tubing and creates uneven shrink.
04
Inspect
Finished tubing should be tight with no bubbles or lifted edges. No adhesive will appear at the ends — this is single-wall tubing. Confirm even recovery across the full length.
Size ReferenceExpanded vs.
Expanded vs.
recovered.
Actual 1" tube at full expanded diameter (25.4mm) and after heat recovery. Use this as your fit reference before cutting.
Expanded: 25.4mm — slides over 300–400 MCM
Shrink ratio: 2:1 on full heat
Use it on.
01
Large Cable Bundle Management
Consolidates and protects the largest cable bundles in industrial facilities, data centers, and power distribution environments.
02
Harness Band Marking
Provides large-diameter band identification on industrial wire harnesses for maintenance, commissioning, and future troubleshooting.
03
Pipe & Hose Identification
Identifies pipes, hoses, and conduits in process plants, mining operations, and heavy manufacturing facilities.
04
Panel Entry Strain Relief
Applied at the point where large cable bundles enter panels and enclosures to distribute mechanical stress and prevent jacket wear.
05
Cable Tray Finishing
Provides a clean finished end cap on cable tray bundles at termination points in industrial and commercial electrical installations.
06
Industrial Mechanical Protection
Covers large cable assemblies in environments where abrasion, oil, and mechanical contact are present but submersion is not.
Size Guide
1" Questions.
Technical Guides
All Guides →From the Blog
Free Tool
Heat Shrink Size Calculator
Read Guide →Ratios2:1 vs 3:1 vs 4:1 Heat Shrink Ratio Guide
Read Guide →Uses2:1 Heat Shrink Uses — Bundling & More
Read Guide →SizingSize Chart & Selection Guide
Read Guide →ComparisonHeat Shrink vs Electrical Tape
Read Guide →Buyer's GuideBest Heat Shrink Tubing 2026
Read Guide →Also available — 1" in other lines
All 13 sizes.
View line overview →3/32"2.4mm120 ft1/8"3.2mm120 ft3/16"4.8mm120 ft1/4"6.4mm120 ft5/16"8mm120 ft3/8"9.5mm120 ft1/2"12.7mm120 ft5/8"16mm90 ft3/4"19.1mm90 ft
Current1"25.4mm90 ft
1-1/4"31mm60 ft1-1/2"38mm60 ft2"50.8mm60 ftRecovered diameter is approx. 1/2 of the expanded size shown · All sizes ship to USA & Canada