IN-LINE NON-RETURN VALVE; TYPE: DUO-CHECK; CLASS: CLASS 125; NOMINAL SIZE: 4"; MOUNTING TYPE: FLANGES ACCORDING TO ANSI B1 6.1; FLUIDS: WATER, AIR, OIL. MAXIMUM TEMPERATURE 550 ?F (287 ?C); SHAPE: STRAIGHT; WORKING POSITION: HORIZONTAL; BODY MATERIAL: CAST IRON; RETENTION MECHANISM MATERIAL: STAINLESS STEEL; DIMENSIONS ACCORDING TO STANDARD: ANSI B16.34; BODY: CAST IRON DISCS: STAINLESS STEEL SPRINGS: STAINLESS STEEL AISI 316 AXLES: STAINLESS STEEL AISI 304 SEAL: BUNA-N ENDS: WA FER ANSI 125