Size: 18 in. X 18 in. Includes Hawken Dura Max Heat Exchanger, all Fittings & Thermostat. This is a top of the line heat exchanger and has more fins per square inch than most competitor's, which means that when the temperatures drop below zero the cheaper ones have a hard time keeping up. Don't get stuck with something that cant keep up with the demand. The Dura Max is a quality product.
