This product is based on the actual needs of the home , pumping and testing pool (water tower) to control the water level to achieve control. It has the characteristics of small size, simple wiring, low power consumption, switching capacity, strong interference and stable function. When you turn it on automatically, you can pump the pump ( valve) stably (water tower), and automatically stop the pump (solenoid valve) when it is full of water. Local flooding can also be used for automatic drainage, such as garages, basements, etc. Board size: 7cm x 4cm (length * width) This product does not require the purchase of another probe, and the home wiring can be used of the probe. Note: The probe is a wire mesh shell with plastic buckle wire, which can directly induce household wires. The head of the wire is stripped about 2 cm, making it impossible to directly sense. Another: the product does not include the (probe) Colour: as shown Material: PCB Package Contents: 1 * Liquid level switch sensor Only the above package content, other are not included. Note: Light and different displays may cause the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.