A pressure gauge measures air pressure in the air tank and the pressure to the line from the air regulator. Be sure your gauges are accurate; if it is reading the pressure inaccurately it can damage the pump and other components and if the safety valve fails, the tank could explode. Moisture rusts/damages the gauge over time so they must be periodically replaced. Gauges can be air filled or liquid-filled.
This item fits the following models:
15-pc Thunderbolt Black Oxide Drill Bit Set
1/4" x 50 Ft Noodle Air Hose with Coupler and Plug