From police officers to home inspectors, flashlights are essential tools for people who work in a variety of fields. They help people see in the dark, and they also serve as an important communication device. For instance, police use flashlights to illuminate their vehicles when they are stopped at night. They are useful for checking to make sure someone is safe in a car, and they are sometimes used to signal other officers who are on patrol.
A flashlight is a portable, light-producing device that consists of the following parts: Batteries, case, contacts, switch and lamp (light bulb). In most flashlights, the lamp contains either an incandescent tungsten filament or a light-emitting diode (LED), which glows when electricity flows through it. Some flashlights have a different color of light than other lights, which can be useful for improving nighttime visibility or for attracting certain animals and fish to an area.