... the medium in pipes. FSF20W- 3/4 Magnetic flow switch is control switch that directly get signals from the flow of medium ... .FSF20W- 3/4 Magnetic flow switch can be widely used in foodstuff industry, water-cooling air ... -condition, petroleum and petrifaction, etc.FSF20W- 3/4 Magnetic flow switch has lots of advantage, such as simple usage, small bulk ...