Series 3900 pressure switches are widely used in pilot duty applications and incorporate field adjustable set points and internal switch contacts. These switches convert a pressure signal to an electrical output. In response to a change in pressure, movement of an elastomeric diaphragm opens or closes an electrical circuit based on a predetermined pressure set point. The Series 3900 feature a compact size and a cost effective, combination terminal design which allows electrical connection with either 1/4" quick connect or #8 screw terminals. Pressure ranges as low as 6" Water Column (W.C.)* up to 5 PSI are available (1.5 kPa to 34.5 kPa). Series 3900 switches assure control stability through wide temperature and humidity conditions. As with all Tecmark® products, Series 3900 switches provide superior performance and uninterrupted service, even under extreme shock and vibration.