•  Cooler pipes and cooler hoses are refrigerant passages.

•  Refrigerant flows inside of each pipe and hose in the form of high-pressure gas from the A/C compressor to condenser, in the form of high-pressure liquid from the condenser to the expansion valve, and in the from of low-pressure gaseous from the expansion valve to the A/C compressor.

•  The diameter of each pipe is different according to the state of the refrigerant.

•  To prevent O-rings from falling off while piping work is being performed, stay-on O-rings are used at the piping connections.