High Pressure Regulating Valve The Mark 6800HP Series is a self-operated pressure regulating valve for use on high pressure industrial gas and liquid services to 4000 psi (276 bar). The Mark 6800HP features exceptional accuracy with high flow capacities and simple in-line maintainability. For durability and dependable service, the 1/2" - 1" valves are constructed of total barstock, with all stainless steel components. Valve plugs are available with either hard or soft seats and balanced trim is available with either seat type. USDA and FDA approved soft goods available upon request. Gas and liquid services (non-cavitating)