1、The probe is 12" long for extra large planters. 2、Usage: To measure the PH and Moisture value of different kinds of soil. 3、This meter can measure pH and moisture at depths up to 12 inches. No batteries are required. 4、Accuracy: ±0.2ph-suitable for agricultural field and classroom experiments. 5、The Accurate pH 8 utilizes the electronic ground field effect of the earth on two dissimilar metals. Feature: The probe is 12" long for extra large planters. Usage: To measure the PH and Moisture value of different kinds of soil. This meter can measure pH and moisture at depths up to 12 inches. No batteries are required. Accuracy: ±0.2ph-suitable for agricultural field and classroom experiments. The Accurate pH 8 utilizes the electronic ground field effect of the earth on two dissimilar metals. Instructions: Step 1: Switch moisture/pH/light position. Step 2: Stick the probe into the soil about 2-4 inches. Step 3: Adjust the position of the probe until the pointer on the dial swing slightly. Step 4: After 10 minutes, Note moisture/pH/light level in the dial. Step 5: Remove probe from soil and wipe clean after each use. Speciation: Soil acidity meter technical parameters: PH range: 3-8 PH; moisture range: 1-80% PH accuracy: ±0.2PH; moisture accuracy: ±1% Ambient temperature: 5-50 ° C Measurable depth: 6cm Size: 5 x 16.5cm / 1.97 x 6.50 inch (appr.) Package included: 1 x Humidity Monitor Detector PH Soil Meter Note: Please note that the new type and old type of this product will be sent randomly, and make sure you will not mind before ordering.