This cabin altimeter with a differential pressure indicator is intended to measure simultaneously both the pressure altitude and the differential pressure in a pressurised cabin of an aeroplane in relation to the ambient environment. The altitude range is between 0 and 50,000 ft and the differential pressure range is between -1.6 and +5.6 psi. There is also a version with an illuminated instrument face (supply voltage: 5, 14, 28 VDC - according to customer requirements).