The high and low pressure chambers are separated by a sensor assembly consisting of a magnet, a diaphragm and a spring, the difference in pressures causes the sensor assembly to move proportionally through spring resistance.

A rotating magnet located in a body isolated from the pressure chamber, it rotates due to the effect of the linear movement of the sensor assembly magnet, an indicator needle coupled to the rotating magnet indicates the pressure differential in the sphere. Switch operation: a reed sensor.

It is placed adjacent to the pressure chamber and is activated by the magnet of the sensor assembly. The instruments are calibrated with a maximum error of +/- 3% of full scale in ascending readings. For pressure measurement of fans and blowers, obstruction of filters, air speed, pressure drop in orifice plates, hydraulic pressures in fluidic amplifiers, hydraulic systems.