This filter is designed with a copper outer screen to control and destroy destructive mollusks. The body is made of corrosion-resistant PVC, with 2 inch check valve included. The middle and inner screens are made of woven encapsulated vinyl that is both mildew-resistant and 90 lb puncture-proof. The middle and inner screen mesh weave comes in standard 17x11S, and a finer optional 36x11R mesh.  The outer screen cover consists of  copper wire cloth with a 16x16 weave. The ions in the copper are toxic to mussels thus discouraging attachment to the filter. Filter easily disassembles for cleaning without removing check valve from pump suction line.