A manifold-mounted pilot-operated check valve (also called a "PO Check" valve or "Pilot-to-Open Check" valve, is a type of hydraulic valve designed to hold loads in position without allowing them to drop or move uncontrollably. While they may seem similar to counterbalance valves, PO Check valves are best suited for load holding or position holding applications where precise control over fluid flow is not necessary. They are typically more affordable than counterbalance valves and are effective in preventing leakage. However, for applications where load control during motion is required, such as in mobile equipment, a counterbalance valve is the preferred choice. Counterbalance valves offer modulating capabilities, allowing for precise control of actuator movement and preventing over-speeding of the pump, especially in situations where loads may go "over-center" and create negative loads. Ultimately, the choice between a PO Check valve and a counterbalance valve depends on the specific requirements of the hydraulic system and the level of control needed over load movement. If you're not sure of the most suitable option for your application, please call OneHydraulics technical support and we will be happy to help you make the right choice.