The heater tube assembly carries hot water from the vehicle engine cooling system to the heater core. The heater core is located under the dash inside the passenger compartment. A fan blows air across the heater core providing a comfortable environment for the passengers during cool weather. The heater tube has many different designs and specifications and this depends on which vehicle the heater tube assembly will be attached.

The heater tube is commonly a 15.87499 mm (0.625 inches) diameter low carbon steel tube of varied lengths. The manufacturing of this product involves many processes such as; endforming, tube bending, welding, leak testing, painting and final assembly and pack.