The paddle type SPDT WFS series are designed to provide excellent performance where accuracy, reliability, and rugged construction are required used in liquid flow lines carrying water or any fluid neither harmful to brass and prosphor bronze nor classified as a hazardous fluids. They can be wired to close one circuit and open a second circuit when liquid flow either exceeds or drops below the adjusted flow rate. The WFS series are recommended for liquid pressure and temperature as mentioned below and must not be used on lines carrying liquids below 0°C. These series may be used on liquids with high salt or chlorine content but is not for use in hazardous atmospheres. They may be also used outdoors but must be protected from weather or splashing water.