Tecmark® Series 4000 Pressure Switches convert a positive or negative pressure signal (range 2” W.C. to 100 PSI) to an electrical output. Tecmark® Pressure Switches are available in various configurations for air, gas and liquid sensing applications. Tecmark® switches can sense pressures as low as 2" w.c. up to 100 PSIG with electrical ratings up to 25 amps.