Lumatek 240v BallastHigh performance with low power consumption and operating cost make the LUMATEK Digital Ballast 250W a great ballast for beginner and professional growers of light sensitive crops. A ballast is necessary to light high intensity discharge (HID) lamps such as high pressure sodium (HPS) and metal halide (MH) grow lamps. Depending on the type of crop and light cycle required, ballasts run continuously 8 24 hours a day and must therefore be as efficient as