The Luster Leaf Rapitest Digital Soil pH Meter (1845) is an improved thin meter style that offers you the most convenient way to read digital output. The digital meter determines the alkalinity or acidity level of container soil and garden. The long stainless steel probe monitors the soil pH at root level. Checking the soil pH of the plant guarantees optimal conditions for growth. Also, this forbids over and under watering. Once purchase, this includes the printed plant list and the batteries needed. The Digital Soil pH Meter is specifically designed for soil only.