Gauge Sensors are sensors that show pressures above atmospheric pressure -- when exposed to the atmosphere they will report a reading of zero pressure. Gauge sensors are designated by a 'g' or the word 'gauge' at the end of the rated pressure reading range.

Absolute Sensors are sensors that show the pressure based on an absolute scale starting with zero being a perfect vacuum. These sensor exposed to the atmosphere will show approximately 1 bar (1.013 at sea level), or lower at higher elevations. Abosolute sensors are designated by an 'a' or the word 'absolute' at the end of the rated pressure reading range.