Heat Exchanger Water to Air, 18"x 20" with 3-Row 3/8" Copper Ports, 242 Aluminum Fins Heat Exchanger for Outdoor Wood Furnaces, Residential Heating and Cooling, and Forced Air HeatingProduct Features High Quality Materials The entire unit is copper brazed at edges and contact points, forming a durable and leak resistant piece that withstands high pressure and temperature. CE certified for reliable quality. Durable and Corrosion Resistant Features epoxy coated fins, providing high hardness, wear resistance, and corrosion protection. This reduces internal water vapor scaling, promoting maximum heat exchange between air and fins.