Engine Oil and Automatic Transmission Oil CoolerOur compact all aluminum Heat Sink cooler uses both external and internal fins to maximize heat transfer. With a 3" diameter it can be mounted in a variety of locations and the universal design can be used to cool a wide variety of components. Perfect for fuel and power steering applications, this powerful little heat exchanger can also be used to cool engine oil and transmission fluid in light duty applications. Includes hose barbs.