... /airproof ring, water seal ring, water valve/hydrovalve 1)Material:Corundum, mullite, corundum alumina, 95%~99% Alumina, Zirconia Ceramics2)Variety ... : ceramic ring, ceramic cup, ceramic needle/ball/base etc erose ... good for health4)Application widely used for seal ring, water seal ring, water valve/hydrovalve ceramic sealing part/ ...