This handy meter measures soil moisture at the root level to prevent over or underwatering. No batteries are needed, so there is nothing to replace or wear out. It includes an instruction booklet, watering guide, and special needs information for 15o plants that correspond to meter readings. Range: 0 (dry) to 10 (wet). Size: 4"L x 2 1/2"W x 1 1/2"H. Probe: 4 1/4"L.