Brazed plate heat exchangers suitable for heating or cooling. Four ports allow for 2 liquids to flow in and out of each heat exchanger. The high surface area path provides an interface for efficient heat transfer. Ideal for heating oils or fuels in oil conversions such as SVO, UVO, WVO. Heat shower water for camping showers by using the hot coolant in your vehicle. Using a ball valve on the inlet of the coolant allows you to vary the flow and the temperature of your end water.