Fluval 3-Pack Fine Filter Pads are specially designed for Fluval FX5 High Performance Canister Filters. These polyester pads capture small particles and debris that can cloud water and help keep water clear. The pads should be used in conjunction with Fluval Water Polishing Pads to optimize the purity of aquarium water. Features: Made from fine polyester material for effective particle pickup Includes: 3 Fine Filter Pads (medium) Water Type: Aquarium; freshwater and marine Fluval FX5 Filter Medium-Fine Pad Aquarium Tank Media | PetSmart