Features: Great for fish tanks, to promote gas exchange and increase dissolved oxygen levels. Great for tropical fish farms, koi ponds, waste water systems, etc. For use with wet/dry filters (here is not included), to improve biological filtration. Aiding in the critical gas-exchange process that is needed for successful biological filtration. Specifications: Color: Black Material: Environmental Plastic Quantity: 100pcs Dia: 18mm / 0.7in Package Size: Approx. 21 * 14 * 2cm / 8.27 * 5.5 * 0.79in (L * W * H) Package Weight: 152g / 5.35oz Package List: 100 * Bio Balls
