State-of-the-art electronic, compact fluorescent bulbs are the smallest sized full-spectrum, energy saving lights available. These compact fluorescent bulbs fit into a variety of light fixtures such as table lamps, wall sconces and track lights. These bulbs are cost effective replacing your high-wattage, short-lived incandescent bulbs. Full spectrum compact fluorescent bulbs 6400 Kelvin, provide natural color comparable to sunlight, increases visual activity and reduces eye fatigue. These bulbs are excellent for indoor greenhouse applications, where the suns natural light is not available. Use 6400K for growth & 2700K for budding or flowering stages. Requires E39 socket.