The red light in flashlights helps preserve night vision by interfering less with the eye's ability to adjust to darkness. It is less conspicuous to wildlife, which is useful when hunting and observing nature. It is used as a signal or warning light because it is easily visible even in fog or smoke. It reduces glare, making it more pleasing to the eyes when reading and working at night or when camping. In rescue and tactical operations, it provides sufficient illumination without giving away the position.