... electronic ballast.Welthink series digital electronic ballast can run HPS and MH bulbs both automatically under 100V~240V, 277V, ... Constant output of power and light when voltage varies between -15%~15% of rating voltageProtection functions: Open circuit and short circuit ... ,CUL, EMC, ROSH,CE,TUV.Suitable Bulbs400W, 600W, 1000W HPS/MH bulb of America and Europe standard Electrical Performance of ...