TruePower 1000Watt HPS MH Digital Dimmable Ballast Up to 30% energy savings compared to transformer technology. Operates stably with voltage range from 106 to 260 Volts, 50-60 Hertz, extending bulb life, and in temperatures from -58 Fahrenheit to 122 degrees. Hot bulb thermal protection: automatic circuit break until bulb has cooled or 8 minutes has passed. Open and short circuit protection. Built in fan cooling and thermal absorbing circuit board foam.