PVC Heat Shrink Tubing 2:1 Ratio – Flat Shrinkable Tube for Wire & Cable (7mm–23mm)

Select a tube whose flat (pre-shrink) width is at least 1.5–2× the diameter of the wire or connector you need to cover. With a 2:1 shrink ratio, the recovered inner diameter will be roughly half the listed flat width. For example, a 12mm flat-width tube typically recovers to approximately 6mm. When in doubt, size up one step for easier installation.

This tubing uses a 2:1 shrink ratio, meaning it shrinks to approximately half its original flat diameter when heat is applied. This is the most common ratio for general-purpose wire insulation and bundling tasks. For tighter fits over irregular shapes, a 3:1 or 4:1 ratio tubing is generally recommended instead.

PVC heat shrink tubing generally activates at temperatures around 70–90°C (158–194°F). A heat gun set to low or medium is typically sufficient. Move the heat gun steadily along the tube to shrink evenly from one end to the other. Avoid open flames, which can scorch or melt the material unevenly and create weak spots.

PVC heat shrink tubing provides basic moisture resistance and is generally suitable for light indoor and semi-protected outdoor use. For fully waterproof or submersed applications — such as marine wiring or underground cable splices — an adhesive-lined (dual-wall) heat shrink tubing is typically recommended instead. Contact us to confirm suitability for your specific environment.

As a general guide based on the 2:1 shrink ratio:

• 7mm flat — typically fits wires up to ~3–4mm diameter
• 9mm flat — typically fits wires up to ~4–5mm diameter
• 12mm flat — typically fits wires up to ~6mm diameter
• 15mm flat — typically fits wires up to ~7–8mm diameter
• 17mm flat — typically fits wires up to ~9mm diameter
• 18.5mm flat — typically fits wires up to ~10mm diameter
• 23mm flat — typically fits wires up to ~12mm diameter

Always verify against your specific wire or connector diameter before cutting.

Yes. This tubing is available in 16 colors including Black, White, Red, Blue, Green, Yellow, Transparent, and more. Color-coding is a widely used practice in automotive, electronics, and industrial wiring to identify circuits at a glance and reduce troubleshooting time. Simply select your preferred color from the variant options above.

Use sharp scissors or a utility knife for clean, straight cuts. Cut the tubing slightly longer than the area you need to cover — in most cases 5–10mm extra on each end — to account for any end-shrinkage that occurs during heat application. Slide the cut piece over the wire before making your solder joint or connection, then position and shrink.