Dr.Meter Soil Moisture Meter S30, Sunlight PH Acidity 3-in-1 Soil Tester Kit for Garden Farm Lawn Planter 3-in-1: tests moisture, PH value and light level using two 20cm probe and a light sensor High accuracy and Rapid respond: there are three calibration tables, you can respectively get the accurate value immediately No Battery Needed: because it neednt any battery or electricity. Just plug in the probe to your object Compact and portable: it is convenient to use it indoor, outdoor or in your greenhouse Promote Healthy plants: it ensures and maintains the health and quality of your greenery. By using it, you can know when to water, control PH level and whether the plant getting adequate sunlight