55W/65W Compact FL 50/50 Aquarium Lamp in White Nanometer Range: 420nm Blue/10K White One side is a true super actinic blue 03 420nm that promotes photosynthesis essential for the health of corals & invertebrates Second side is a 10,000K super daylight w/full spectral output essential for the health of plants, coral & invertebrates Great bulb to use on systems with only compact fluorescent bulbs for an even light spread Intensifies the beauty & vibrant color in fish, coral & marine life