General description Bio Balls are designed to enhance the filtration process in aquariums and other aquatic systems. They promote gas exchange and increase dissolved oxygen levels, making them ideal for tropical fish farms, ponds, and wastewater systems. These bio balls are specifically for use with wet/dry filters to improve overall filtration efficiency. Technical specifications Color: Black Material: Environmental Plastic Diameter: 16mm Package List: 400 x Bio Balls Measurement allowed error: +/- 1-3 cm