Radar guns are devices used to measure the speed of moving objects, commonly employed by law enforcement to monitor vehicle speeds. They work by emitting radio waves that bounce off the target and return to the device, allowing it to calculate the speed based on the frequency change of the returned waves. These devices are also used in various sports, such as baseball and tennis, to measure the speed of pitches and serves. Radar guns provide accurate and real-time speed readings, making them valuable tools for both safety enforcement and athletic performance analysis.