... made of fiber Sizha knot,compared with the traditional particle filter, the steel ,its elastic effect is better , Detailed Product ... made of fiber Sizha knot,compared with the traditional particle filter, the steel ,its elastic effect is better , non-floating ... diameter15-25,25-30mmporosity96%Ball AppearanceA white oval-shaped ball Common specifications: 20mm /40mm/20-40mm/ 20-50mm If you ...