... , bronze, ductile iron with nylon coated4) Seat: EPDM, NB, BUNA-N, PTFE, VITON 5) Stem: SS410, SS416, SS304, SS316, carbon steel ... ) KEY: carbon steel (WCB)8) O ring: EPDM, NBR, BUNA-N 9) Bushing: PTFEFor catalog, pls visit www.metalvalves.com Butterfly Valves ...