... ) Medium: R134a, R22, R407C, R404A/507, Water and oil 3) Material: Brass Oil Flow Switch FSF series :FSF20W- 3/4 Magnetic flow ... current: 1AAvailable medium: R134a, R22, R407C, R404A/R507, oil and mixture of oil and refrigerant. Type data ModelConnection size(inch)Flow rate ... -G3/4G3/450FSF20W-3/43/4” ODF148FSF25W-9/81” ODF194 Oil Flow Switch FSF series