Heat Shrink Ratio 2:1 vs 3:1 vs 4:1 Explained
The shrink ratio decides how big a step one sleeve can cover. Pick it from the diameter jump in your assembly.
What the ratio is
Ratio = supplied ID ÷ recovered ID. A 2:1 sleeve shrinks to half its expanded diameter; 3:1 to a third; 4:1 to a quarter.
Which to pick
No step, just the wire → 2:1 (dual-wall). One sleeve over a connector and onto a wire → 3:1 or 4:1 (3:1/4:1 dual-wall).
Recovery tip
Heat evenly with a heat gun; don't spot-heat or the wall recovers unevenly. Full range under products by performance.
Frequently asked questions
Which ratio covers a connector and a wire?
3:1 or 4:1 so one sleeve passes the barrel and grips the wire.
Is a higher ratio always better?
No — higher ratios have thicker expanded walls; use the lowest ratio that fits the step.
Do all materials come in 4:1?
Dual-wall adhesive is stocked in 2:1, 3:1 and 4:1.