What heat shrink tubing does
Heat shrink tubing is a sleeve that shrinks tightly onto a cable or joint when heated, providing insulation, abrasion resistance, strain relief and — in adhesive-lined versions — an environmental seal.
Shrink ratio
Shrink ratio is how far the tube collapses — 2:1, 3:1 and 4:1 are the most common. A higher ratio covers larger connectors and uneven shapes; choose 3:1 or 4:1 for connectors and splices, 2:1 for simple insulation.
Material and temperature
Polyolefin covers general-purpose use; FEP and PTFE tubes handle 200 °C and beyond for demanding automotive, aerospace and chemical environments, with fluoropolymers adding superior chemical resistance.
Certifications to check
For export, look for UL, RoHS and REACH compliance as a minimum, plus IATF 16949 for automotive programmes. These confirm safety, environmental and quality-system compliance.