Although they are in the same range with inline check valves, DC Series Hydraulic Double Pilot Operated Check Valves are different in that they permit the valve to open normally closed direction, or they provide a positive shut-off by means of a specific pilot pressure signal. Fluid is directed towards one of the valve ports and free flow to the corresponding port. Then by moving the pilot piston the pressure opens opposite check valve and provides a return passage for fluid through the opposite check valve. DC Series have excellent seal due to the heat treatment applied to internal components.