A Pitot-static tube is a device that is commonly found in aircraft and is used to measure the airspeed of the vessel. Some synonyms for this term include a Prandtl tube, a Pitot tube, a Pitot probe, or a pressure tube. These devices work by measuring the velocity pressure of the air using a small opening at the end of the device, while also measuring the static pressure using a perpendicular opening. This allows pilots and engineers to accurately calculate the airspeed of a vessel and make necessary adjustments. Overall, regardless of the name used, the function of these devices is crucial in ensuring that aircraft and other vessels operate safely and effectively.