Dk-Lok V63 Series 1/4" 10-250PSI Adjustable Pressure Relief Valve 316SSV63 Series 1 4" 10 250PSI Adjustable Pressure Relief Valve 316SS DK LOK V63 66 series proportional relief valves provide a wide range of set pressures in order to protect your systems against over pressurization resulting in damage to system components. These proportional relief valves open in direct relation to how quickly the system inlet pressure overcomes the set pressure of the spring. They close in direct relation to how quickly the system inlet