Flashlights are portable light sources that use battery, electrical, or mechanical power to illuminate an area or item for inspection. They are made of aluminum, plastic or other lightweight materials and used in emergency, military, and maintenance applications.

Today flashlights use mostly incandescent lamps or light-emitting diodes and run on disposable or rechargeable batteries. Some are powered by the user turning a crank or shaking the lamp, and some have solar panels to recharge a battery.

Some flashlights are approved for use in gaseous or hazardous environments. Others are exceptionally durable. Although most flashlights are cylindrical in design, products such as headlamps or headlights are often rounded. High-performance tactical flashlights are also available.