Screens currently come in three aperture sizes that will restrict flow on nozzles to compensate for system flow and pressure. These are fixed flow rate screens so refer to the performance sheet to apply the correct screen to the PSI of your system or components.
Black: .6 GPM @30PSI
Purple: .46 GPM @30PSI
White: .34 GPM @30PSI
Brown .2 GPM @30PSI
For fine tuning utilize the adjustment screw on the nozzle if applicable.