helps control and regulates the pressure but also works as a flow proportionate valve with high and low flow.
1/4 Inch Thread Small - 1000 PSI (0.15 GPM & 0.30 GPM) & 1500 PSI ( 0.15GPM)
1/4 Thread Big - 1500 PSI ( 0.30 GPM)
3/8 Thread Big - 1500 PSI ( 0.5 GPM, 1 GPM, 2 GPM)