Digital ballast. 1000W, 600W, 500W and 400W MH/HPS compatible , 120V/240Vconvertable UL,CUL, CE,TUV, listed No fans ... inside The features of the Welthink series Grow light ballast,digital ballast.Run for HPS and MH lamps both.High power factorPF≥0 ... : UL,CUL, EMC, ROSH,CE,TUV. Suitable Bulbs250W, 400W, 600W, 1000W HPS/MH bulb of America and Europe standard Electrical Performance of ...