This is the valve most people actually want when they say "flow control". It meters the flow in one direction and lets it return completely unrestricted through an internal check valve.

Fit it in a cylinder line and you get a slow, controlled extend with a full-speed retract — or the other way round, depending on which way you plumb it. Fit it in a motor line and you set the speed one way without choking the return.

Meter in or meter out? Metering the flow out of a cylinder gives far better control on an over-running load, because the oil on the outlet side is doing the holding. Metering in is fine for a resistive load and slightly more efficient.

Cracking pressure of the reverse free flow check: 0.05 MPa (a) or 0.4 MPa (b) depending on build.

Hydraulic fluid: mineral oil or phosphate ester. Fluid temperature −20 to +70 °C. Viscosity 2.8 to 380 mm²/s.