NEPTUNIA N1C DUO check valve, maintenance not required Application fi elds For liquids in the industrial range, general services, water treatment, Not suitable for media with solid components. Face to face dimension according to DIN EN 558-1 Max. working pressure 16 bar Rating PN10, PN16, other ratings on request Temperature range -10°C ÷ 90°C with Nitrile (NBR) O-ring -10°C ÷ 120°C with EPDM O-ring, -10°C ÷ 150°C with Viton® (FPM) O-ring,