LAARS Stainless Steel indirect Water Heater, Single Wall, 179 First Hour Delivery: Minimum Heat Required Rate 105,000 BTU/Hour, Continuous Flow (gal): 160 gal/hour The Laars-Stor SS utilizes a superior grade of type 444 passivated stainless steel for the tank and the heat transfer coil. This construction is lightweight and also resists pitting while minimizing inter-granular and stress corrosion. The Laars-Stor SS models provide superior thermal conductivity for higher efficiency.