{"product_id":"black-heat-shrink-tubing-2-1-large-diameter-20mm-210mm-20cm","title":"Black Heat Shrink Tubing 2:1 — 20mm to 210mm Large Diameter, 20cm Piece","description":"\u003cscript type=\"application\/ld+json\"\u003e\n{\n  \"@context\": \"https:\/\/schema.org\",\n  \"@type\": \"FAQPage\",\n  \"mainEntity\": [\n    {\n      \"@type\": \"Question\",\n      \"name\": \"How do I choose the right diameter for my cable or conduit?\",\n      \"acceptedAnswer\": {\n        \"@type\": \"Answer\",\n        \"text\": \"Measure the outer diameter of your cable bundle, conduit, or pipe end. Choose a heat shrink size where the expanded inner diameter is at least 10\\u201320% larger than your cable. With a 2:1 shrink ratio, the tubing shrinks to approximately half its listed diameter after heat is applied. For example, 40mm tubing shrinks to approximately 20mm. When in doubt, size up \\u2014 a slightly oversized tube will still shrink down tightly.\"\n      }\n    },\n    {\n      \"@type\": \"Question\",\n      \"name\": \"What does the 2:1 shrink ratio mean for large-diameter tubing?\",\n      \"acceptedAnswer\": {\n        \"@type\": \"Answer\",\n        \"text\": \"A 2:1 shrink ratio means the tubing shrinks to approximately half its original expanded diameter when heat is applied evenly. For large diameters, this is especially important: 100mm tubing shrinks to approximately 50mm, and 210mm tubing shrinks to approximately 105mm. Always verify your cable or conduit dimensions against the selected variant before ordering.\"\n      }\n    },\n    {\n      \"@type\": \"Question\",\n      \"name\": \"Can this large-diameter heat shrink tubing be used outdoors?\",\n      \"acceptedAnswer\": {\n        \"@type\": \"Answer\",\n        \"text\": \"Black polyolefin heat shrink tubing generally offers better UV resistance than clear or colored variants, making it suitable for light outdoor use including sealing conduit ends, protecting outdoor cable splices, and covering pipe joints in electrical enclosures. For long-term direct UV exposure, submersion, or direct burial, additional weatherproofing is typically recommended.\"\n      }\n    },\n    {\n      \"@type\": \"Question\",\n      \"name\": \"What tool do I need to shrink large-diameter tubing?\",\n      \"acceptedAnswer\": {\n        \"@type\": \"Answer\",\n        \"text\": \"A heat gun with adjustable temperature settings is strongly recommended for all sizes in this range (20mm\\u2013210mm). Apply heat in a slow, even sweeping motion from the center outward to avoid trapping air or creating wrinkles. For very large diameters (100mm and above), work slowly and methodically around the full circumference. A lighter or hair dryer is not recommended for these sizes.\"\n      }\n    },\n    {\n      \"@type\": \"Question\",\n      \"name\": \"Is this tubing electrically insulating?\",\n      \"acceptedAnswer\": {\n        \"@type\": \"Answer\",\n        \"text\": \"Yes. Polyolefin heat shrink tubing is generally electrically insulating and is widely used for insulating large cable splices, sealing conduit ends, and protecting exposed conductors in industrial and marine electrical installations. Always verify the voltage rating is appropriate for your specific application. Contact us if you need confirmation of the dielectric rating.\"\n      }\n    },\n    {\n      \"@type\": \"Question\",\n      \"name\": \"Is 20cm enough for my application?\",\n      \"acceptedAnswer\": {\n        \"@type\": \"Answer\",\n        \"text\": \"Each piece is 20cm (approx. 7.9\\\") long before shrinking. This is typically sufficient for sealing a single conduit end, covering a cable splice, or capping a pipe joint. If you need longer coverage, you can order multiple pieces and overlap them slightly. For continuous long-run coverage, consider our cut-to-length heat shrink tubing listings.\"\n      }\n    },\n    {\n      \"@type\": \"Question\",\n      \"name\": \"What applications is this large-diameter heat shrink tubing suitable for?\",\n      \"acceptedAnswer\": {\n        \"@type\": \"Answer\",\n        \"text\": \"This large-diameter black heat shrink tubing is typically used for sealing and protecting conduit ends and pipe joints in outdoor electrical enclosures, covering large cable bundle splices in industrial and marine wiring, providing strain relief and abrasion protection on thick power cables, capping and sealing the ends of cable trays and conduit runs, and protecting large-diameter hoses and tubing in automotive and industrial applications.\"\n      }\n    }\n  ]\n}\n\u003c\/script\u003e\n\n\u003cdiv class=\"hdiy-desc\"\u003e\n\n  \u003cdiv class=\"hdiy-overview\"\u003e\n    \u003ch2\u003eBlack Heat Shrink Tubing 2:1 Large Diameter — 20mm to 210mm, Ready-Cut 20cm Pieces\u003c\/h2\u003e\n    \u003cp\u003eWhen you need to seal a conduit end, cap a large cable splice, or protect a thick power cable bundle, standard small-diameter heat shrink just won’t cut it. Electricians, industrial maintenance technicians, marine riggers, and automotive builders working with large cable assemblies need a reliable large-diameter heat shrink tubing that ships ready to use — no cutting a roll, no guessing how much you need for a single joint.\u003c\/p\u003e\n    \u003cp\u003eEach piece of this black heat shrink tubing is 20cm (approx. 7.9\") long and uses a 2:1 shrink ratio. Available in 11 diameters from 20mm (approx. 3\/4\") to 210mm (approx. 8.3\"), covering mid-size cable bundles through very large conduit and pipe ends. The tubing is made from polyolefin material, which is electrically insulating, flame-retardant, and resistant to moisture, abrasion, and common chemicals. Each listing is sold as 1 piece per order.\u003c\/p\u003e\n    \u003cp\u003eTypical applications include sealing and protecting conduit ends and pipe joints in outdoor electrical enclosures, covering large cable bundle splices in industrial and marine wiring installations, providing strain relief and abrasion protection on thick power cables and battery leads, and capping the ends of cable trays and conduit runs in commercial electrical work.\u003c\/p\u003e\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"hdiy-compat\"\u003e\n    \u003cspan class=\"hdiy-compat-icon\"\u003eℹ️\u003c\/span\u003e\n    \u003cstrong\u003eSize guide:\u003c\/strong\u003e The listed diameter is the expanded (pre-shrink) inner diameter. With a 2:1 ratio, the tubing shrinks to approximately half that size after heat is applied. Select a diameter at least 10–20% larger than your cable bundle or conduit outer diameter for a snug, wrinkle-free fit.\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"hdiy-note\"\u003e\n    \u003cspan class=\"hdiy-note-icon\"\u003e⚠️\u003c\/span\u003e\n    \u003cstrong\u003eApplication note:\u003c\/strong\u003e A heat gun is required for all sizes in this range. For diameters 100mm and above, work slowly around the full circumference to ensure even shrinkage. Each piece is 20cm (approx. 7.9\") long — order multiple pieces if longer coverage is needed. Contact us to confirm suitability for high-voltage or specialty applications.\n  \u003c\/div\u003e\n\n  \u003ch2\u003e✅ Key Features of These Large Diameter Black Heat Shrink Tubing Pieces\u003c\/h2\u003e\n  \u003cul class=\"hdiy-features\"\u003e\n    \u003cli\u003e\n\u003cspan class=\"hdiy-icon\"\u003e📐\u003c\/span\u003e\u003cspan\u003e\u003cstrong\u003e11 Large Diameter Options\u003c\/strong\u003e — From 20mm (approx. 3\/4\") to 210mm (approx. 8.3\"), this range covers mid-size cable bundles through very large conduit ends and pipe joints in a single listing.\u003c\/span\u003e\n\u003c\/li\u003e\n    \u003cli\u003e\n\u003cspan class=\"hdiy-icon\"\u003e✂️\u003c\/span\u003e\u003cspan\u003e\u003cstrong\u003eReady-Cut 20cm Pieces\u003c\/strong\u003e — Each piece is pre-cut to 20cm (approx. 7.9\"), eliminating the need to measure and cut from a roll for single-joint conduit sealing, cable splice protection, or pipe end capping.\u003c\/span\u003e\n\u003c\/li\u003e\n    \u003cli\u003e\n\u003cspan class=\"hdiy-icon\"\u003e🔥\u003c\/span\u003e\u003cspan\u003e\u003cstrong\u003e2:1 Shrink Ratio\u003c\/strong\u003e — Shrinks to approximately half its expanded diameter with even heat gun application, conforming tightly to irregular cable shapes, conduit ends, and connector profiles for a secure, professional finish.\u003c\/span\u003e\n\u003c\/li\u003e\n    \u003cli\u003e\n\u003cspan class=\"hdiy-icon\"\u003e⚡\u003c\/span\u003e\u003cspan\u003e\u003cstrong\u003eElectrically Insulating Polyolefin\u003c\/strong\u003e — The polyolefin construction provides reliable electrical insulation for large cable splice protection, conduit end sealing, and exposed conductor coverage in industrial, marine, and automotive wiring.\u003c\/span\u003e\n\u003c\/li\u003e\n    \u003cli\u003e\n\u003cspan class=\"hdiy-icon\"\u003e💧\u003c\/span\u003e\u003cspan\u003e\u003cstrong\u003eMoisture \u0026amp; Abrasion Resistant\u003c\/strong\u003e — The tubing wall resists moisture ingress, mechanical abrasion, and common chemicals, making it suitable for outdoor electrical enclosures, marine cable management, and industrial cable protection.\u003c\/span\u003e\n\u003c\/li\u003e\n    \u003cli\u003e\n\u003cspan class=\"hdiy-icon\"\u003e🔥\u003c\/span\u003e\u003cspan\u003e\u003cstrong\u003eFlame-Retardant Material\u003c\/strong\u003e — Polyolefin heat shrink tubing is generally flame-retardant, providing an added layer of safety in industrial and automotive wiring applications where heat and spark exposure is a concern.\u003c\/span\u003e\n\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003ch2\u003e📐 Technical Specifications — Large Diameter Black Heat Shrink Tubing\u003c\/h2\u003e\n  \u003cdiv class=\"hdiy-table-wrap\"\u003e\n    \u003ctable\u003e\n      \u003ctbody\u003e\n        \u003ctr\u003e\n\u003cth\u003eColor\u003c\/th\u003e\n\u003ctd\u003eBlack\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eShrink Ratio\u003c\/th\u003e\n\u003ctd\u003e2:1\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eMaterial\u003c\/th\u003e\n\u003ctd\u003ePolyolefin (flame-retardant)\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003ePiece Length\u003c\/th\u003e\n\u003ctd\u003e20cm (approx. 7.9\")\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003ePack Size\u003c\/th\u003e\n\u003ctd\u003e1 Piece per order\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eAvailable Diameters (Expanded)\u003c\/th\u003e\n\u003ctd\u003e20mm (approx. 3\/4\"), 25mm (approx. 1\"), 28mm (approx. 1-1\/8\"), 30mm (approx. 1-3\/16\"), 35mm (approx. 1-3\/8\"), 40mm (approx. 1-9\/16\"), 45mm (approx. 1-3\/4\"), 50mm (approx. 2\"), 60mm (approx. 2-3\/8\"), 70mm (approx. 2-3\/4\"), 210mm (approx. 8.3\")\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eWall Thickness (Pre-Shrink)\u003c\/th\u003e\n\u003ctd\u003eSee variant options\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eOperating Temperature Range\u003c\/th\u003e\n\u003ctd\u003eContact us to confirm\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eElectrical Insulation\u003c\/th\u003e\n\u003ctd\u003eYes (polyolefin)\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eFlame Retardant\u003c\/th\u003e\n\u003ctd\u003eGenerally yes — contact us to confirm rating\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eRecommended Application Tool\u003c\/th\u003e\n\u003ctd\u003eHeat gun (required for all sizes in this range)\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eTypical Applications\u003c\/th\u003e\n\u003ctd\u003eConduit end sealing, large cable splice protection, pipe joint covering, strain relief on power cables, industrial \u0026amp; marine wiring\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003c\/tbody\u003e\n    \u003c\/table\u003e\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"hdiy-faq\"\u003e\n    \u003ch2\u003e❓ Frequently Asked Questions\u003c\/h2\u003e\n\n    \u003cdetails\u003e\n      \u003csummary\u003eHow do I choose the right diameter for my cable or conduit?\u003c\/summary\u003e\n      \u003cdiv class=\"hdiy-faq-body\"\u003e\n        \u003cp\u003eMeasure the outer diameter of your cable bundle, conduit, or pipe end. Choose a heat shrink size where the expanded inner diameter is at least 10–20% larger than your cable. With a 2:1 shrink ratio, the tubing shrinks to approximately half its listed diameter after heat is applied. For example, 40mm tubing shrinks to approximately 20mm. When in doubt, size up — a slightly oversized tube will still shrink down tightly.\u003c\/p\u003e\n      \u003c\/div\u003e\n    \u003c\/details\u003e\n\n    \u003cdetails\u003e\n      \u003csummary\u003eWhat does the 2:1 shrink ratio mean for large-diameter tubing?\u003c\/summary\u003e\n      \u003cdiv class=\"hdiy-faq-body\"\u003e\n        \u003cp\u003eA 2:1 shrink ratio means the tubing shrinks to approximately half its original expanded diameter when heat is applied evenly. For large diameters, this is especially important: 100mm tubing shrinks to approximately 50mm, and 210mm tubing shrinks to approximately 105mm. Always verify your cable or conduit dimensions against the selected variant before ordering.\u003c\/p\u003e\n      \u003c\/div\u003e\n    \u003c\/details\u003e\n\n    \u003cdetails\u003e\n      \u003csummary\u003eCan this large-diameter heat shrink tubing be used outdoors?\u003c\/summary\u003e\n      \u003cdiv class=\"hdiy-faq-body\"\u003e\n        \u003cp\u003eBlack polyolefin heat shrink tubing generally offers better UV resistance than clear or colored variants, making it suitable for light outdoor use including sealing conduit ends, protecting outdoor cable splices, and covering pipe joints in electrical enclosures. For long-term direct UV exposure, submersion, or direct burial applications, additional weatherproofing measures are typically recommended. Contact us to confirm suitability for your specific outdoor environment.\u003c\/p\u003e\n      \u003c\/div\u003e\n    \u003c\/details\u003e\n\n    \u003cdetails\u003e\n      \u003csummary\u003eWhat tool do I need to shrink large-diameter tubing?\u003c\/summary\u003e\n      \u003cdiv class=\"hdiy-faq-body\"\u003e\n        \u003cp\u003eA heat gun with adjustable temperature settings is strongly recommended for all sizes in this range (20mm–210mm). Apply heat in a slow, even sweeping motion from the center outward to avoid trapping air or creating wrinkles. For very large diameters (100mm and above), work slowly and methodically around the full circumference. A lighter or hair dryer is not recommended for these sizes — they do not provide sufficient or even heat for large-diameter tubing.\u003c\/p\u003e\n      \u003c\/div\u003e\n    \u003c\/details\u003e\n\n    \u003cdetails\u003e\n      \u003csummary\u003eIs this tubing electrically insulating?\u003c\/summary\u003e\n      \u003cdiv class=\"hdiy-faq-body\"\u003e\n        \u003cp\u003eYes. Polyolefin heat shrink tubing is generally electrically insulating and is widely used for insulating large cable splices, sealing conduit ends, and protecting exposed conductors in industrial and marine electrical installations. Always verify the voltage rating is appropriate for your specific application before use. Contact us if you need confirmation of the dielectric rating for a particular use case.\u003c\/p\u003e\n      \u003c\/div\u003e\n    \u003c\/details\u003e\n\n    \u003cdetails\u003e\n      \u003csummary\u003eIs 20cm enough for my application?\u003c\/summary\u003e\n      \u003cdiv class=\"hdiy-faq-body\"\u003e\n        \u003cp\u003eEach piece is 20cm (approx. 7.9\") long before shrinking. This is typically sufficient for sealing a single conduit end, covering a cable splice, or capping a pipe joint. If you need longer coverage, you can order multiple pieces and overlap them slightly for a continuous seal. For continuous long-run coverage, consider our cut-to-length heat shrink tubing listings available in 1M–25M lengths.\u003c\/p\u003e\n      \u003c\/div\u003e\n    \u003c\/details\u003e\n\n    \u003cdetails\u003e\n      \u003csummary\u003eWhat applications is this large-diameter heat shrink tubing suitable for?\u003c\/summary\u003e\n      \u003cdiv class=\"hdiy-faq-body\"\u003e\n        \u003cp\u003eThis large-diameter black heat shrink tubing is typically used for sealing and protecting conduit ends and pipe joints in outdoor electrical enclosures, covering large cable bundle splices in industrial and marine wiring, providing strain relief and abrasion protection on thick power cables and battery leads, capping the ends of cable trays and conduit runs in commercial electrical work, and protecting large-diameter hoses and tubing in automotive and industrial applications. The 210mm option is particularly suited to very large conduit or pipe end sealing.\u003c\/p\u003e\n      \u003c\/div\u003e\n    \u003c\/details\u003e\n\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"hdiy-cta\"\u003e\n    🛒 Select your diameter above, then add to cart — ships from our US warehouse.\n  \u003c\/div\u003e\n\n\u003c\/div\u003e","brand":"HomeDIYer","offers":[{"title":"20mm \/ 1 Piece","offer_id":52330639982866,"sku":"ZXCGZYYSG0518x1","price":4.56,"currency_code":"USD","in_stock":true},{"title":"25mm \/ 1 Piece","offer_id":52330640015634,"sku":"ZXCGZYYSG0519x1","price":4.69,"currency_code":"USD","in_stock":true},{"title":"28mm \/ 1 Piece","offer_id":52330640048402,"sku":"ZXCGZYYSG0520x1","price":5.48,"currency_code":"USD","in_stock":true},{"title":"30mm \/ 1 Piece","offer_id":52330640081170,"sku":"ZXCGZYYSG0521x1","price":4.69,"currency_code":"USD","in_stock":true},{"title":"35mm \/ 1 Piece","offer_id":52330640113938,"sku":"ZXCGZYYSG0522x1","price":5.66,"currency_code":"USD","in_stock":true},{"title":"40mm \/ 1 Piece","offer_id":52330640146706,"sku":"ZXCGZYYSG0523x1","price":4.91,"currency_code":"USD","in_stock":true},{"title":"45mm \/ 1 Piece","offer_id":52330640179474,"sku":"ZXCGZYYSG0524x1","price":5.13,"currency_code":"USD","in_stock":true},{"title":"50mm \/ 1 Piece","offer_id":52330640212242,"sku":"ZXCGZYYSG0525x1","price":5.3,"currency_code":"USD","in_stock":true},{"title":"60mm \/ 1 Piece","offer_id":52330640245010,"sku":"ZXCGZYYSG0526x1","price":6.01,"currency_code":"USD","in_stock":true},{"title":"70mm \/ 1 Piece","offer_id":52330640277778,"sku":"ZXCGZYYSG0527x1","price":6.46,"currency_code":"USD","in_stock":true},{"title":"210mm \/ 1 Piece","offer_id":52330640310546,"sku":"ZXCGZYYSG0528x1","price":23.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0884\/8936\/1682\/files\/Main-02_03343d93-eecd-4e1c-b9cb-c17458549175.jpg?v=1780905115","url":"https:\/\/homediyer.com\/de\/products\/black-heat-shrink-tubing-2-1-large-diameter-20mm-210mm-20cm","provider":"HomeDIYer","version":"1.0","type":"link"}