Ultra Sun Dual Arc Tube Lamp The Ultra Sun™ Dual Arc Tube Lamp offers the best of both worlds with a 600 watt HPS and a 400 watt MH arc tube both inside one lamp jacket, operating simultaneously. This full spectrum lamp has a 3,000°K color temperature achieved by the dual arc tubes working together. This lamp is an excellent choice for full term growth, flowering and fruiting. The Dual Arc Tube lamp operates on a standard 1000 watt HPS magnetic ballast or an electronic ballast such as the Galaxy brand. These lamps have been specifically engineered for horticulture applications. Ultra Sun™ lamps are high quality, feature robust construction and have excellent reliability at an economical price. One year warranty.