Wilkerson® by Dixon® R21-02RG dial Air Regulator with GC230 Gauge, 1/4 in NPT/BSPP-G, 117 scfm Flow Rate, 0 to 160 psig Adjustable Pressure. Wilkerson® by Dixon® R21-02RG dial Air Regulator with GC230 Gauge, 1/4 in NPT/BSPP-G, 0 to 160 psig Adjustable Pressure