Penn Plax Small World replacement filter cartridge for FC1

Smallworld replacement filtration cartridges contain two filtration units. Replacement filtration cartridges are designed to fit Smallworld filter unit. (SWF1) Filtration cartridges work to keep fish healthy. Smallworld filtration cartridges keep aquarium water looking crystal clear for 2-4 weeks. Cartridges are easy to replace and easy to dispose of. Replacement cartridges fit on any shape tank.