Galaxy? Commercial 1000 watt 277 volt ballast can operate a 1000 watt HPS, MH or DE lamp at 50%, 75%, 100% or 110% settings. The Galaxy? Commercial ballast comes pre-wired with a Sun System? lamp cord receptacle. It is compatible with all Sun System? branded reflectors. Includes a 6 ft 277 volt power cord with L7-15P twist lock plug. Efficient >98% PF operates 1000 watt HPS/MH and DE lamps, smart start feature, fully sealed extruded aluminum housing, lightweight and quiet operation. Compliant with FCC Article 18 Part A (governs commercial use) as tested by an independent US testing lab in a true as used configuration. Operates at 72 kHz.