The probe can be inserted directly into the soil. This is a digital display soil moisture. When the humidity is below the set value, start the pump to start watering, and stop watering when the humidity reaches the set value. It's very simple. Note: Follow the wiring diagram shown. You can choose the appropriate wiring according to the applied load voltage. 1. F0 set stop humidity (the humidity of solenoid valve or water pump stops working): Press the & ;SET& ; button to display & ;F0& ;, press the & ;SET& ; button to display the starting humidity, and press the + / button to & ;SET& ; the humidity value 2. F1 set start humidity (start humidity of solenoid valve or pump): Press +/- to switch to & ;F1& ;, press & ;SET& ; to display the stop humidity value, and press +/ to SET the humidity value 3. F2 humidity correction: There is no need to correct errors in normal use. Using multiple modules at the same time to correct values is beneficial to uniform management operations Specification: Working voltage: DC 12V Control current: 0-10A Humidity range: 20-99%RH Control accuracy: 1%RH Size: 52x43x16mm/2.05x1.69x0.63inch Weight: about 28g Package Includes: 1 x Soil Moisture Sensor Controller Relay Module