Features: This product is suitable for replenishing water in fish tanks with cylinder- wall thickness of 5/6mm and -8mm. Match with international standard coke-bottle. Usage: It can be used for the fish tanks wall with -8mm thickness, and it has two states- corresponding to the fish tanks wall with 5mm and 6mm thickness respectively. Cut_off the differential pressure pipe (the water contact end is an oblique-mouth), a long one and a short one, and the short one is the highest water level line-. When the short pipe is completely exposed- to the liquid surface~, it will start to replenish- water, and the short pipe will stop to replenishing water. This product needs to bring its own water replenishing bottle, and the thread of the product is suitable for domestic national standard coke-bottles. Built-in noise reduction device can effectively reduce noise. (Note: not completely silent). The length of the tubing (manually cut) allows you to adjust the water level. Specifications: Material: ABS- Length: Approx. 3cm/1.18inch Inner Diameter: Approx. 2.7cm/1.06inch Outer Diameter: Approx. 3.5cm/1.38inch Package Includes: 1x Water Replenishing Device note: 1.Please allow 1-2cm errors due to manual measurement, make sure that you do not mind before you order. 2.Due to the differences between different monitors, the picture may not reflect the actual color of the item.