8x Filter Net Bag - Pond bio ball Breeder MEDIA aquatic - The filter bag is made with corrosion-resistant materials. - When using it, put the filter medium into the net bag, and then place into the filter tank. - The filter net is in compact size. - It is suitable for pack filter material, such as bio ball, activated carbon, ceramic and ammonia remover. SIZE22.7CM(8.9'') X 12.8CM(5'')