Cool Deluxe grow bulb Sunmaster Cool Deluxe Grow Lamps emit light from 5000° to 6500° Kelvin, imitating the natural look of daylight. They are an ideal light source for the seedling and vegetative stages of plant growth, while still emitting a wide spectral distribution. The 600w Sunmaster Metal Halide Cool Deluxe Lamp has a lumen output of 55000 all of which is in the blue part of the spectrum making them ideal for vegetative growth creating plants with shorter internodes setting them on a course to heavy yields. The Sunmaster range of lamps has proven to be excellent value for money providing reliability and quality lamps time and time again. Horticultural lamp light output will decrease with use. We recommend that growers replace lamps at regular intervals to maintain optimum yields.