1. Water Detector: The water level sensor has two parts, alarm body and probe adhered to a sucket cup. Once the probe is soaked by water, alarm sounds. 2. Easy Use: Juck suck the sucket cup to the inside of fish tank glass(adjust the positon by your own demand), leave the alarm body outside. When the feet of the detector was immersed by water, it will give alarms. 3. Simple Maintain: The water leak sensor is powered by replacable CR2032 button battery. If not working well, disassemble the back shell, check the battery, whether the motherboard plug is loose. Fasten the plug or replace the battery will solve problems. 4. Wide Application: Suitable for aquarium fish tank water level monitoring, monitoring home tank water level, sump water level, and other applications. 5. Durable: Made of engineering plastics and electronic components, it is resistant to aging and has a long service life. Specification: Material: Plastic Color: White Size: Approx.4x4x1.5cm/1.57x1.57x0.59, Cord Length Approx.17cm/6.69in Package Includes: 1 Piece Water Level Sensor Note: 1.Please allow 0-1cm error due to manual measurement. pls make sure you do not mind before you bid. 2.Due to the difference between different monitors, the picture may not reflect the actual color of the item. Thank you 3. Please dry the probe with tissue after using. Except for the probe, other parts cannot touch water. 4.After receiving the product, if there is any dissatisfaction, please contact us directly online, do not directly give us a bad review, we will properly handle your problem, please be sure to give us a five-star praise.