... , R407C, R404A/507, Water and oil 3) Material: Brass Oil Flow Switch FSF series :FSF20W- 3/4 Magnetic flow switch is mainly used to ... monitor and control the flow of the ... : R134a, R22, R407C, R404A/R507, oil and mixture of oil and refrigerant. Type data ModelConnection size(inch)Flow rate range(L/min)Medium ...