Description: Material: Fish tank water level controller is made of pp material, which is sturdy and wear resistant, can be used for a long time. Product Size: Automatic water replenisher for fish tank measures 3cm in length with an outer diameter of 3.5cm and an inner diameter of 2.7cm. The card slot spacing can be adjusted according to your needs, making it versatile and user-friendly. Design: This automatic fish tank water replenisher features a side hole design that prevents the formation of back pressure bubbles, ensuring smooth and efficient operation. Multifunction: 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. Application: Suitable for tank wall thicknesses of 5mm, 6mm, 8mm. Equipped with a pressure buckle that replaces the sealing ring, this water level controller guarantees no leakage, keeping your aquarium clean. Specification: Material: PP Size Chart: Length: 3cm/1.18inch Outer Diameter: 3.5cm/1.38inch Inner Diameter: 2.7cm/1.06inch Package Includes: 5 Pieces Fish Tank Water Level Controller Note: Please allow slightly errors 1-2cm differences due to manual measurement.