Introduction to Mil-Spec Shrink Boots

Sleek Alternative to Metal Backshells

Shrink boots are an alternative to metal backshells that provide superior strain relief and environmental sealing for applications requiring low-profile backshells. When used in conjunction with specially designed boot adapters, shrink boots are an alternate way to environmentally seal a jacketed cable to a connector. Shrink boots, when used with a banding boot adapter can also provide complete environmental and EMI/RFI protection.

Shrink boots are made from polyolefin, a semi-flexible material that is low-smoke and flame retardant. When heat is applied, the boot shrinks or “recovers” over the boot adapter and an adhesive lining bonds to the boot adapter and cable, forming a tight environmental seal. Shrink boots must always be used with an appropriate boot adapter to ensure strain relief and environmental protection.

Shrink boots come in straight and 90° configurations and feature operating temperatures of -67° to +392°F (-55° to +200°C). Activation temperature is approximately 248°F (120°C). A high-quality heat gun with adjustable temperature is recommended for professional installation of shrink boots. Milnec offers shrink boots in the following thermoplastic materials:

  • Viton® pre-coated with latent-curing hot-melt epoxy
  • Elastomer pre-coateded with polymide adhesive
  • Low-smoke, zero-halogen pre-coated with adhesive

Boot Adapters

For proper installation, shrink boots must be used with boot adapters. The basic boot adapter provides a specially designed platform for the boot to grip, providing effective IP67 environmental protection. An EMI/RFI banding boot adapter features internal hardware that enables easy cable shield termination for electromagnetic and radio frequency interference protection, in addition to environmental protection. A simple hand tool is all that is required for the banding process.


A high-quality heat gun is recommended for proper shrink boot installation. Milnec offers a professional heat gun with adjustable temperature settings and reflector tips suitable for all shrink boot applications.

If using the EMI/RFI banding boot adapter, a banding tool must be used. The one-step banding tool is the only tool needed to place, tighten, and trim bands for shield termination on EMI/RFI banding boot adapters. One size band fits all adapter sizes, making shield termination reliable and easy.