It's no need for batteries or electricity ,just plug and read. Soil moisture meter make your plants can grow healthy and strong(Do not use it to test pure water directly. Simply push the meter into the soil and you'll get your reading. This machine is sophisticated, it's not complicated! With an interface using ten scales and a color-coded reading system from red, green to blue, it's never been more straightforward reading your soil moisture. It can easy and accurately to read moisture promotes healthy plants and flowers. Why not eliminate the guesswork and keep your hands clean when you use the Soil Moisture Sensor Meter! Know the right time to water your garden, farm, lawn and plants, anytime.