[High quality and environmental protection]-The products are environmentally friendly and have no effect on water quality and fish. This Feeding Ring comes complete with suction cup and plastic floating ring to retain floating foods and help prevent food from entering the filter. [Fixed point feeding]-Fixing the feeding area, increasing the feeding rate, helping the fish to develop a habit of eating at a fixed position. [Reduce pollution]-Effectively enclose the feed, reduce feed waste and water pollution, and keep the water tank clean and thorough. [ Rotating device]-The feeding circle can change the position of the hover with the change of the water level. It is adjustable, simple and convenient. Improves feeding efficiency and supports better water quality by reducing the amount of uneaten food decomposing within the gravel and filter system. Specification: Material: PVC Color: Black, Blue Shape: Square, Round Size Chart: Size Round: Outer Diameter: 7.5cm/2.95inch Inner Diameter: 5.5cm/2.16inch Square: Outer Diameter: 10cm/3.93inch Inner Diameter: 8cm/3.14inch Package Includes: 1 Piece Aquarium Feeding Circle