Function: Aquarium Water Change Valve Can Be Used to Change the Water Quantitatively Every Time and Can also Be Used to Add Water. Multi-Size: 12mm Valve Is Suitable For Hose With Inner Diameter of 12mm/0.5inch and External Diameter of 16mm/0.6inch, 16mm Valve Is Suitable For Hose With Inner Diameter of 16mm and External Diameter of 22mm/0.9inch. High Quality: Our Hose Valve Is Made of Plastic With Special Design, For Long-time Use. Wide Use: Suitable For Fresh Water and Salt Water, also Can Be Used For Devices Such as Filters, Pump Return Lines, Protein Skimmers, Etc. SHOP WITH CONFIDENCE: To Provide You With the Highest Quality Service, If You Have Any Question, Please Contact Us.We Will Provide After-sales Service ., Manufacturer: DONGKER