Oil Flow Switch FSF series : 1) Connection: 3/4"ODF 2) Medium: R134a, R22, R407C, R404A/ ... 3) Material: Brass Oil Flow Switch FSF series :FSF20W- 3/4 Magnetic flow switch is mainly used to monitor ... signals from the flow of medium.FSF20W- 3/4 Magnetic flow switch can be widely used in ... air-condition, petroleum and petrifaction, etc.FSF20W- 3/4 Magnetic flow switch has lots of advantage, such as ...