B Series switches are designed to handle pressure from vacuum to 210 kg/cm². These are designed for high proof pressures. B series switches use a diaphragm sealed piston actuator. As the pressure on the calibrated piston increases, the adjusted spring force is over-come and the snap action switch is actuated. The piston is sealed from the process by a diaphragm. Choice of diaphragm materials offer compatibility with virtually any medium. A welded stainless steel actuator is, also available as an option from 0.05-1 kg/cm² to 3.5-70 kg/cm² ranges.