The Fluval Universal Filter Media Bag measures approximately 16.5 cm x 25.4 cm- 6.5 x 10 and each package contains 2 bags. Ideal for use in all Fluval canister filters. This media bag is easy to use all you need to do is top up the bag with sufficient filter media, fasten the bag with the enclosed fastener and set the filled media bag in the preferred section. Plastic fasteners included Makes media maintenance even simpler Convenience and control for smaller media Fine mesh to contain resins Safe for fresh or salt water Made of durable nylon