Top Fin Retreat Rf-S Filter Cartridges (Small) Refill (6 Count)

This contains a 6 month supply of RF-S filter cartridges. Top Fin Small Retreat filter cartridges have activated carbon to help get rid of organic waste odors and heavy metals. Please replace every 3-4 weeks. Compatible with 2 Gallon Modern Betta Aquarium 3 Gallon Easy-Clean Glass Aquarium 3 Gallon Rose Gold Style Aquarium and 3.5 Gallon 360 degree Betta Glass Aquarium.