VHO Ballast: . Microprocessor controlled. . Low operating temperature extends ballast life by 30%. . Automatic protection function: Over loading, over current, short circuit. . Can fire with 1, 2, 3 or 4 lamps. Others work normally when one or more lamps end its life. . Size: 28.6*8.1*4.5(cm) Length*Width*Height . OEM ODM welcome.