An air brake coil (also known as a coiled air hose or suzie coil) is a flexible, helical pneumatic line that transmits compressed air between a tractor truck and a trailer to operate the vehicle's braking system. The tightly coiled design allows the lines to expand and contract smoothly as the truck turns, preventing the hoses from sagging, tangling, or dragging on the deck plate.

Nylon tubing is primarily categorized by its chemical formulation, which determines its flexibility and environmental resistance:

• Nylon 11 (PA11) & Nylon 12 (PA12): The industry standard for pneumatic lines and fuel systems. They offer low moisture absorption, excellent dimensional stability, and superior resistance to UV light, oils, and hydraulic fluids. PA11 is often bio-based and slightly more flexible than PA12.
• Nylon 6 (PA6) & Nylon 6/6 (PA66): More rigid variants with higher mechanical strength and melting points. They are commonly used for structural fluid lines but absorb more moisture, which can affect their dimensions and pressure ratings in humid environments

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