Hydraulic flow control valves permit safe, simple and repeatable control of hydraulic fluids at operating pressures to 5000 psi. The standard slotted control spindle allows for a wide range of infinitely variable flow adjustments with excellent flow characteristics. Precise adjustment of flow is achieved by a micrometer style adjustment knob featuring a color coded flow indicator for accurate, easy-to read visual flow reference. Design modifications and special materials are available for corrosive fluids such as phosphate ester, acids and caustics.