... Ductile Iron Disc and PTFE SeatDesign to comply with MSS SP-67, BS5155, and API 609 Compatible ... : Body materials: cast iron, ductile iron, and stainless steel Disc: ductile iron (with nickel-plated ... nylon-coated), SS 304, 304L, 316, and 316L Seat: PTFE Shaft: SS410, SS416 Pin: SS316 O-ring ... : NBR, EPDM, Neoprene, and Viton Bushing: PTFE, nylon, and lubricated ...