DFROBOT Gravity: Analog Capacitive Soil Moisture Sensor- Corrosion Resistant New Year Holiday Promotion ingThis analog capacitive soil moisture sensor measures soil moisture levels by capacitive sensing, rather than resistive sensing like other types of moisture sensor Insert it into soil and impress your friends with the real-time soil moisture data This module includes an on-board voltage regulator which gives it an operating voltage range of 3.3 ~ 5.5V This sensor is compatible with DFRobot 3-pin "Gravity" interface, which can be directly connected to the Gravity I/O expansion shield. Download User Guide on this page for more. (Technical Specification - User Guide) It is made of a corrosion resistant material giving it a long service life. Product wiki&gt;&gt;https://www.dfrobot.com/wiki/index.php/Capacitive_Soil_Moisture_Sensor_SKU:SEN0193 Supports Gravity 3-Pin Interface Analog Output Gardening &amp; Farming Moisture Detection Intelligent Agriculture Operating Voltage: 3.3 ~ 5.5 VDC Output Voltage: 1.2 ~ 2.5 VDC Interface: PH2.0-3P Dimension: 98mm * 23mm (3.86in x 0.905in) Weight: 15g Capacitive Soil Moisture Sensor x1 Analog Sensor Cable x1