The Galaxy Grow Amp 1000 Watt ballast can operate a 1000 watt lamp at 400 watts, 600 watts, 1000 watts & Turbo Charge. The Galaxy Grow Amp ballast can operate a 750 watt lamp at 600 watts & Turbo Charge a 750 watt lamp. The Galaxy Grow Amp 600 Watt ballast can operate a 600 watt lamp at 400 watts & Turbo Charge a 600 watt lamp. These ballasts will properly drive 400 Watt HPS/MH, & 600 watt HPS lamps or properly drive 400 Watt HPS/MH, 600 watt HPS & 1000 watt HPS/MH lamps. Set the desired wattage on the Select-A-Watt dial & install the correct lamp. Galaxy Grow Amp ballasts come pre-wired with a Sun System lamp cord receptacle. They are compatible with all Sun System branded reflectors. Includes a 6 foot 120 volt power cord. Purchase a 240 volt power cord separately (#903082). Specifications: extremely efficient - 99.9%; 902215 - operates 400 watt HPS/MH & 600 HPS lamps, 902235 operates 600 HPS and 750 HPS/MH lamps, 902220 operates 400, 600 and 1000 HPS/MH lamps, soft starting, extruded aluminum housing, fan cooled for superior thermal management, lightweight, very quiet and limited vibration, voltage: 120 or 240, Part No. 902225 is 240 volt only.