The 6700K fluorescent lamp from ESU emits wavelengths closer to the red/orange end of the spectrum, wavelengths used by plants for photosynthesis. It outputs a warm white light that also displays your plants, artificial or real, and your freshwater fishes to their fullest natural beauty. A great daylight lamp choice for health and viewing in freshwater tanks. The T-5 size outputs the same amount of light as a T-8 or T-12 fluorescent bulb in less space. Installs in a T-5 fluorescent fixture.