SYLVANIA 400 W HPS-GROWLUX FOR GROWTH AND BLOOMThis bulb can be used for growth and bloom. the light is mostly red yellow spectrum, needed for the flowering stage but it also has 30% more of the blue spectrum (for the vegetative stage). Patented arc tube delivers the highest photosynthetic efficiecy Performance maintained at an exceptional level due to improved structure of the outer bulb, Optimised for the highest Phytolumens or PAR output Industry leading lumen maintenance of 95% at the end of