... ballast.Welthink series digital electronic ballast can run HPS and MH bulbs both automatically under 100V~240V, 277V, 347V, 400V ... short circuit protection functions available.Easy installationEasy to hang the lamp, no need any external starter and compensation capacitor.Completely ... light soluaitons are available UL CUL CE TUV listed HPS/MH electronic ballast,250W,320W,400W,500W 600W, 800W,1000W