Interstate Pneumatics CPE7034 16" Discharge Tube for C2000 Air Compressor 1/4" ID, 3/8" Threaded NPT Heat Sink Metal Fins 16 inch Long Note: The main line that carries compressed air from the pump head to the air tank, the discharge (or transfer) tube is typically made of copper, aluminum or stainless steel braided material. Be sure all compression fittings and threads have tight seals and dont leak, and replace if kinked or cracked.