Pressure relief valves are the safeguards that limit maximum pressure in a system by diverting excess gases when pressure gets too high. The pressure at which a relief valve first opens to allow fluid to flow through is known as cracking pressure. Sequencing valves are normally closed two-way valves, and they regulate the sequence that various functions in a circuit will occur. They resemble direct-acting relief valves. Direct-acting valves arepressure-reducing valves that limit the maximum pressure available in the secondary circuit regardless of pressure changes in the main circuit. This assumes the work load generates no back flow into the reducing valve port. Counterbalance valves are typically closed and are often used to maintain a set pressure in a portion of a circuit, usually to counterbalance a weight. The style of valve is ideal for counterbalancing an external force or to counteract a weight like in a press to keep it from free-falling