GB61-40T40-P American Water Heaters 40 Gallon Atmospheric Vent Propane Water Heater6-year limited Tank warranty, 6-year parts warranty for Residential applicationsIntelligent Control Logic-The internal microprocessor provides enhanced operating parameters and tighter differentials for precise sensing and faster heating response to optimize performanceHigh Energy FactorsGreen Choice® Gas Burner -Patented eco-friendly burner design reduces NOx emissions by up to 33% and complies with Low-NOx emission requirements of less than 40 ng/JCoregard™ Anode Rod - Our anode rods have a stainless steel core that extends the life of the anode rod allowing superior tank protection far longer than standard anode rodsBlue Diamond® Glass Coating - Provides superior corrosion resistance compared to industry standard glass lining