6600 Series Couplers (hydraulic) up to 5000 PSI, connect with ISO 7241 series A, 6600 Series Nipples. Parker’s 6600 Series have double shut-off poppet valves and are interchangeable with other quick disconnects complying with ISO 7241 series A. These steel couplers and nipples are available in a range of sizes for applications with pressure ranges up to 5000 PSI.