Feature: 1. Corner Shape: The quarter shape of the corner sponge filter increases surface area for better water and oxygen rates, making it easy to hide in the corners of your fish tank. 2. Dual Filtration: The sponge filter provides both mechanical and biological filtration, and the tiny air bubbles created by the air increase the oxygen solubility. 3. Easy to Clean: The bio sponge corner filter is small, easy to clean, and made of bio cotton for better filtration, keeping a transparent water tank. . 4. Easy to Set Up: You can connect to open the air pump (not included), press the sponge into the water tank, fully absorb the water in the water tank, and make it sink to the bottom. 5. Applicability: This bio sponge corner filter will not disrupt the landscape layout of the tank, and is suitable for the cultivation and rearing of various ornamental fish, shrimp or fry. Specification: Item Type: Corner Sponge Filter Material: Bio Cotton, Plastic Application: Fish Tank Corner Sponge Filter. Package List: 1 x Corner Sponge Filter1 x Connecting Tube