Features: 1. Water Detector: The water level sensor includes an alarm body and a probe attached to a suction cup. When the probe comes into contact with water, the alarm is triggered. 2. Easy to Use: Attach the suction cup to the inside of a fish tank glass (adjust position as needed) and place the alarm body outside. When water reaches the detector, an alert will sound. 3. Simple Maintenance: Powered by a replaceable CR2032 button battery. If the device is not functioning properly, remove the back cover, check the battery, and ensure the motherboard connector is secure. Tighten the connection or replace the battery to resolve issues. 4. Wide Application: Suitable for monitoring water levels in aquariums, tanks, sumps, and other similar applications. 5. Durable Design: Constructed from engineering plastics and electronic components, resistant to aging with a long service life. 6. Note: Dry the probe with a tissue after use. Only the probe is water-resistant; all other components must remain dry. Specifications: Material: Plastic Color: White Size: Approx. 4 x 4 x 1.5 cm / 1.57 x 1.57 x 0.59 in Cord Length: Approx. 17 cm / 6.69 in Weight: Approx. 20 g Note: 1. Please allow 0–1 cm error due to manual measurement. Ensure you are comfortable with this before purchasing. 2. Due to differences in monitor displays, the image may not reflect the actual color of the item. Thank you! Package Includes: 1 Piece Water Level Sensor