nylon spiral hose /spiral brake tube 1.smooth inner wall,quick response 2.low pressure loss,friction 3.aging resistance. nylon spiral hose /spiral brake tube1.Material:PA12 PA11 PA6 PU2.Advantages: smooth inner wall,quick response,low pressure loss,friction and aging resistance and good flexibility etc.3.Usage: the air brake connections for various tractors,trailers and trucks.