Feature: 1. These biological filter balls have a large surface area to allow germ to multiply. 2. Multiple channels in the surface provide a large amount of water flow, allowing nutrients to reach and support the germ community. 3. Easy to use, can be used in salt water or fresh water, the bio ball does not need to be replaced unless it is damaged or destroyed. 4. This kind of biological ball is very suitable for cartridge filters and pond filters, specially suitable for cartridge filters. 5. High‑quality plastic and ceramic material, suitable for a wide range of environments. 6. Bring an easy‑to‑clean filter mesh, and put the bio balls into the filter mesh to use to achieve a better water purification effect. Specification: Item Type: Aquarium Bio Balls Material: Plastic + Ceramic Product Color: As Pictures Shown Product Weight: Approx. 139g/4.9ozProduct Use: Fish tank filter material Quantity: About 26pcs. Package List: 1 Box Filter1 x Filter Mesh Note: It is recommended to clean the bio balls once every 3 months to achieve a cleaner filtering effect.