... HPSMH compatible No fans inside, digital electronic ballast 1000w. Welthink WEX120 and WEX230 digital ballast are designed specially for hydroponics, greenhouse, ... circuit protection functions available.Easy installationEasy to hang the lamp, no need any external starter and compensation capacitor.Completely ... are available . UL,CUL,CE,TUV certificated digital electronic ballast 1000w,600w,400w,250w