... 3.High lighting efficiency Dimmable Electronic Ballast for HPS /MH Lamp 400W for Grow Light Hold UL, CE, TUV certification approved ... -off Failture ProtectionYesThermal ProtactionYesLamp Failture Protection YesAdvantage:small size, light weight, low operating temperature, rapid install and excellent energy ... saving. 2012 Mew Designed Dimmable Electronic Ballasts for HPS /MH Lamp 400W for Grow Light