BIOLOGICAL FILTRATION: Along with providing a compact and easy-to-handle design, the nylon mesh filter bag helps create a simple solution to aquarium canister filter media replenishment. CLEAN, CRYSTAL-CLEAR WATER: The ring-filled bag helps establish a biological bed for your aquarium, and optimize the colonization of anaerobic bacteria. HELPFUL INSTRUCTIONS: If you notice that the Bio Rings are getting a bit clogged, simply clean them in a separate container with some of your aquarium’s water. This allows for the colony of anaerobic bacteria to remain intact within the porous Bio Rings. MEASUREMENTS: Size = 10 Oz / Quantity = 1-Pack SHOP PENN-PLAX FOR ALL YOUR PET’S NEEDS: PENN-PLAX is a manufacturer and distributor of top quality pet supplies, who specialize in creating excellent pet products for animals, both great and small.