The MicroGlow is a 12 watt plant growth light bulb. Fits standard light bulb sockets. Greens up to 1 to 2 trays of wheatgrass or microgreens at a time. Low electricity use and emits no heat. The energy squeezing MicroGlow showers your plants with the perfect blend of light needed for fast, vigorous growth. The MicroGlow fits into any standard light socket making it the most versatile LED grow light on the market today. Suitable for all stages of growth, the MicroGlow covers 2 square feet as primary lighting and up to 7 square feet as supplemental. 120v, 1 year manufacturer"s warranty.Coverage: Distance to Plants / Light Coverage -20" / 2 sq. ft -40" / 4 sq. ft -60" / 5-3/5 sq. ft -80" / 7 sq. ft Why LED?: LEDs produce light more efficiently, can burn brighter longer, emit virtually no heat and the wavelengths of light can be controlled to the nanometer. This is why LEDs are ideal for growing plants; they are extremely energy efficient and can produce the exact spectrum of light that plants love. In fact, LED"s work so well that NASA uses LED technology to grow plants in space.