... under the distribution of small,it has the following advantages: high efficiency ,filtration rate ,fast, sewage interception capacity, renewable ... m3specific surface area3000m2/m3spherical diameter15-25,25-30mmporosity96%Ball AppearanceA white oval-shaped ball Common specifications: 20mm /40mm/20-40mm/ ... Looking forward to hearing from you soon. fiber-ball filter of high quality and have current goods