The Quantum Series ballast is one of the first ballasts on the market to offer you a dimming switch that enables you to run your ballast at the strength YOU desire. This not only makes it easier to harden off young plants just being introduced to HID lighting, but also allows you to control your footprint and power usage as well. You can increase the power to your ballast as your garden grows and demands more light, and save yourself a substantial amount of money on your power bill over the length of your crop cycle. The Quantum 1000 & 600 watt ballasts power both high pressure sodium & metal halide lamps and run off 110 & 220 power sources. Dimmable down to 75% & 50%, the Quantum provides an additional 30% in efficiency compared to magnetic core ballasts.