The SW-01 fish tank water level alarm is designed to help you monitor your aquarium water volume. Once set at the required parameter, the alarm will beep if the water level increases or decreases within the fish tank. Features: 100% brand new and high quality. Refined from top-quality engineering plastic and electronical elements, the water-level alarm is durable with long service life. The alarm of high/low water level can be adjusted at will according to your requirement. The split type design, sound-light alarm make it convenient for using, while the adoption of button batteries make it could be safely used and easily maintained. In the installation of water-level probe, the point L must be set on the lowest end, and point H must be set on the highest end. Otherwise, the alarm can't work normally. The alarm can't be submerged in water or be wetted. Designed with on / off switch and powered by 3x LR44 button batteries (included). When you replace the batteries, please confirm positive and negative poles. Specifications: Item Type: Water Level Alarm Housing Material: Plastic Color: Black Probe Length: Approx. 2.5cm/0.98in Cable Length: Approx. 120cm/47.24in Alarm Size: Approx. 75cm/2.761.97in Quantity: 1 Set (other accessories demo in the picture is not included) Note: 1.Transition: 1cm=10mm=0.39inch 2.Please allow 0-1cm error due to manual measurement. pls make sure you do not mind before you bid. 3.Due to the difference between different monitors, the picture may not reflect the actual color of the item. Thank you 4.No retail package Package includes: 1 X Water Level Alarm 1 X Probe Cable (split design)