Description: Good Material: Water Level Controller is made of ABS pp, not easily damaged and can be used for a long time.Automatic water addition: is simple to operate. When the water level reaches the set point, the device automatically adds water to the water tank, no electricity required.Compatibility: Top Off can be used with various containers water bottles or other types of containers.Innovative Principle: Water Control uses the principle of pressure difference, easy to place and replenish water, especially suitable for small and medium sized tanks.Wide range of uses: Top Off is suitable for aquariums, tanks, water tanks, water and fresh water tanks, etc. A water compensator can prevent your tank, aquarium, turtle tank or other water tank from running out of water when you are on a business trip or traveling. Size Chart: 3.7cmx3cm/1.46inchx1.18inch Package Includes: 1Water Level Controller Note: Please allow slightly errors 1-2cm differences due to manual measurement.