HQRP 4-pack Bio-Foam pads for Fluval FX5, FX6 Aquarium Filter/High Performance Canister Filters A239, 015561102391 Replacement Coaster HQRP&reg; 4-pack bio foam pads; with HQRP&reg; Coaster; Intensify biological filtration Efficiently capture small particles and debris For freshwater and marine environments 100% Compatible with Original filter; 2 weeks DOA replacement warranty!