Shell: 444 Passivated Stainless Steel;Insulation: Polyurethane Foam;Heat Exchanger: Stainless Steel, Top Mount;Stand: Composite with Leveling Legs;Finish: Black;Control: Digital Aquastat;Max. Operating Temperature: 160 F ( 71 C);Default Setpoint Temperature: 140 F ( 49 C);Max. Working Pressure: 150 PSIG (10.3 bar);Warranty: 10-Year Limited;Provides hot water using boiler energy as the source;Available in 40, 50 and 80 gallon sizes