The Virtual Sun VS1000WDB is a 1000 Watt Digital Electronic Ballast used for 1,000 Watt Grow Light Systems. It is designed specifically for growers who use both High Pressure Sodium (HPS) bulbs and Metal Halide (MH) Bulbs. It provides constant wattage so that it helps minimize bulb flicker which can drastically reduce the life of bulbs. It has a sturdy housing which keeps internal components safe and and at a lower operating temperature. Buy a 1,000 Watt Magnetic Ballast to maximize your yield, while minimizing your investment! A Digital Ballast enables the electrical current to conform to the optimal levels of performance for the bulb being used. This is only possible through digital circuitry. Digital Ballast also produces a more consistent light while also promoting longer lamp life via cleaner power. This ballast also uses power more efficiently which reduces operating costs. While a little more in price upfront, the cost savings over the life of the unit will greatly make up for the extra initial purchase price.