A magnetic ballast employs an inductor to help properly start and regulate electricity for fluorescent, metal halide and other high-intensity discharge (HID) lights. Also called electromagnetic ballasts, they can help effectively light warehouses and outdoor locations because of their durability and resistance to heat and cold. Instant-start ballasts are the most energy efficient, although rapid-start ballasts provide superior lamp life. Use a magnetic ballast from Grainger to help maximize the performance of your industrial lighting.