Corrosion-resistant design: Capacitive touch measurement system avoids probe oxidization. Powerful ICs embedded: NE555DR manufactured by TI working with built-in amplifier, good for capacitive measurement. Plug-and-play: Grove compatible interface(data transmit) and a long-straight pad function as a probe(data collecting). Starter-friendly: Detail start-up tutorials, abundant resources and projects provided in Wiki and Community. The Grove - Capacitive Moisture Sensor (Corrosion Resistant) is a soil moisture sensor based on capacitance changes. Compared with resistive sensors, capacitive sensors do not require direct exposure to the metal electrodes, which can significantly reduce the erosion of the electrodes. Hence, we call it Corrosion Resistant. It is important to note that this sensor can only qualitatively test the humidity of the soil and cannot measure quantitatively. This means when the moisture of the soil rises, the value of the output decreases; conversely, when the humidity decreases, the output value becomes higher. Colour:blue Material:PCB Package Contents: 1 * Soil Moisture Sensor Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.