FS – Series (Flat Spiral Hoses)The spirally sewn PCA hose is the most traditional hose design in the Aviation ground support industry. Most all PCA hose gets dragged on the tarmac which presses the black Thermo Plastic Urethane wear strip that spirals around the exterior of the hose into service. The full half inch high spiral wearstrip shields the lock stitch sewn outer fabric and the Insulated Chambers.