Pulse Start Metal Halide Lamps:Commercial Grade! They are designed specifically to work with high frequency digital ballasts. They are available in 3000K, 7000K and 10,000K The choices available allow growers to mix and match to create a perfect blend of light to meet the specific needs of your plants-from seedlings to mature plants ready for harvest. These lamps are suited to all manufacturers of electronic ballasts and are engineered to withstand the high frequencies generated by these systems (25Khz-130Khz). Using pulse Start Metal Halide lamps with electronic systems assures long and even lamp life with little color shift, or loss.