- Replacement sponge designed for Penn-Plax Cascade aquarium filters - Optimizes the colonization of beneficial aerobic bacteria, essential for biological filtration - Effectively removes ammonia and nitrites, helping to keep aquarium water clean and healthy - Quick and hassle-free installation, ideal for regular filter maintenance - Improves water quality and protects aquatic life - Compatible with Penn-Plax Cascade filter models - Includes 1 biological sponge per package, model CCF229 - Recommended for home and professional aquariums seeking a safe aquatic environment