Reliance 400 Series, 2", Shank Honeywell Gas Control Valve, Foam Insulation Requires Longer Shank Honeywell Electronic Gas Control Valve, Thermostat Powered By 750 Millivolt Generator, Noticeable LED Indicator Light Blinks 1 Time At 3 Second Intervals During Normal Operation, Increased Temperature Control & Accuracy, Integral Spark Igniter, Fits Reliance Standard 400 Natural Gas Water Heaters With Honeywell Control.