Bradford White ICON System Features - Honeywell self diagnostic electronic gas control - Advanced ScreenLok Technology Flame Arrestor design - Resettable thermal switch - Flammable vapor sensor - Automatic Flue Damper - Compatible with Optional Accessory Packages - Factory installed Hydrojet Total Performance System - Vitraglas lining - 3/4" NPT factory installed dielectric waterway fittings - Protective magnesium anode rod - "3" x "4" Snap-Lock draft diverter - T&P relief valve included - 2" Non-CFC foam insulation - Low restriction brass drain valve