A Pitot static tester typically consists of two pressure gauges connected to a tube that can be attached to a port on an aircraft. One gauge measures the static pressure of the air, which is the pressure of the air in the surrounding environment. The other gauge measures the total pressure of the air, which is the pressure of the air as it flows into the tube. By subtracting the static pressure from the total pressure, the Pitot static tester can determine the dynamic pressure of the air, which is the pressure caused by the air flowing past the aircraft. This information can be used to calculate the airspeed of the aircraft, which is a critical parameter for safe flight. https://www.avionteq.com/AirData/Air-Data-Test-Sets