The SUN PBHB-LBN is a pilot-to-open check valve incorporating a counterbalance function, designed primarily for controlling overrunning loads within hydraulic circuits. It allows free flow from the directional valve port (port 2) to the load port (port 1), while managing the flow from port 1 to port 2 via a pilot-assisted relief valve mechanism. The pressure applied to the pilot port (port 3) determines the pressure setting needed to open the valve and allow flow from port 1 to port 2. This cartridge valve is known for its reliability and precise load control capabilities in demanding applications.