... ignition pin,automatic electrical pulse ignition device.3.Over water pressure protection device,4.Water-gas interlock valve device,5.Anti ... -dry combustion protection device.6.Winter-summer switch option for gassaving,7.Anti-freezing device8.Free hand shower,9.ODS ... device is optional,10.20minuntestimer is optional,11.Zero pressure water start for 5L&6L is optional,12.White coated,metallic white ...