Check valves, also known as non-return valves, maintain pressure and prevent backflow in hydraulic systems. Metering valves control the flow rate of hydraulic fluid, regulating the speed of actuators. Together, they provide flow control and load holding in applications requiring precise motion control, such as in excavators and material handlers.
Bosch Rexroth makes a range of check valves and metering valves for motion control, including the electrohydraulic E-Valve for excavators, (list other types here). They can handle flow rates from 40 to 500 lpm (11 to 132 gpm) and operating pressures up to 420 bar (6090 psi) and 460 bar (6,671 psi).
HydraForce also makes check valves but they are cartridge style check valves for flow rates from 0 to 189 lpm (0 to 50 gpm) and can be located in the Cartridge Valves section of this website under Directional Control Valves.