The Series A family of products all have digital indication for monitoring differential pressure. The A1 and A2 give indication with 5 different selectable engineering units for pressure. The difference between the two products is the addition of the ?Process Arch? on the A2 which is designed to mimic the movement of an indicating needle in mechanical differential pressure gauges. The A3 and A4 add additional programming features such as peak and valley indication, 14 selectable engineering units and the ability to function as a flow gauge when used with an airflow sensing device such as a pitot tube by reading directly in air velocity or flow. The difference between the two is the programming display, the A3 uses a LCD and the A4 uses a much brighter easier to read OLED.
