HPS/MH electronic ballast 400W, 600W, 1000W,110V/240V dual voltage MH/HPS compatible UL,CUL,CE,TUV listed No fans inside HPS/MH electronic ballast.Welthink series digital electronic ballast can run HPS and MH bulbs both automatically under 100V~240V, 277V, 347V, 400V.They have been widely used in hydroponics, horticulture, greenhouse and hobby gardening industries,etc. The features of the ...