Digital ballast. 1000W, 600W, 500W and 400W MH/HPS compatible , 120V ... inside The features of the Welthink series Grow light ballast,digital ballast.Run for HPS and MH lamps both.High power ... factorPF≥0.98Low harmonicGeneral harmonic THD≤ 10%High light efficiencyand energy saving.Low power consumptionMore lumens: 20-30% more lumens than ... UL,CUL, CE,TUV, listed 120-240V,1000W,600W,400W, digital ballast