Refill U-tube gauges.

Easier to read than U-tube gauges, these use an inclined scale to measure pressure or velocity changes in air applications. They are also known as manometers.

Commonly used to indicate clogged filters, these gauges display the difference between two pressure or vacuum measurements.

Use these sensors with differential pressure gauges and switches to measure the static pressure drop across air filters, cooling coils, and blowers in air-handling equipment.