Abstract: Pressure flow regulator for use in pneumatic pressure control devices for maintaining a constant predetermined output pressure from a given constant or variable input pressure. The regulator includes a main housing, an inlet port, an outlet port, an air adjustment regulator and an insert assembly forming air passages when installed in the main housing. The insert is formed such that when inserted in a bore machined into a blank, the insert and the bore mate to form chambers and passages needed for pressure regulation of the pneumatic medium, in this case air.