600W Sun Pulse Metal Halide Retro Grow lamps are specially formulated for plants and other living things. These lamps are available in Kelvin ratings of 3k, 4k, 6.4k, & 10k. Full spectrum and specialized spectrum lamps allow you to mix and match to create perfect mixtures for your specific applications. These lamps have also been designed to work with CORE AND COIL BALLASTS. Because our new Sun Pulse lamps are designed to withstand 4-6 kHz pulses, you will experience long and even lamp life approx (20,000 hrs) with little color shift or loss of FT-CD output. Elliptical shaped arc tube for better distribution of light Long Lamp life Low color shift .