Features: Enhancing your Aquariums water circulation with our Automatic Rotating 4Blade Fan Kits, design to simulation natural water flows and promote fish health. This outlet fan kits features a quiet operations and use selected plastic, ensuring durability and a peaceful environment for your fishtanks life. Great for various Aquariums enthusiasts, especially those focused on maintaining great water quality and fish health. Perfect for home use, office, or public aquariums, this fan Kits improve the aesthetic and overall water environment quality. Suitable with most standard Fishtanks setups, the package includes fittings for 20MM or 25MM inner diameters, making installation quick and hassle freely. Specifications: Product Dimension: As pictures shown Component: Plastic Type Option: 01(2cm inner diameter)/02(2.50cm inner diameter) Package Includes: 1 Set Fishtanks Outlet Fan Kits note: Please allow 1-2cm errors due to manual measurement. Due to the differences between different monitors, the picture may not reflect the actual color the item.