A car key is a small device used to start and operate a vehicle. Traditionally made of metal, it often features a unique cut that matches the car's ignition system. Modern car keys may also include electronic components, such as a transponder chip, which enhances security by preventing unauthorized access. In addition to starting the engine, car keys can also control other functions, such as locking and unlocking doors. Some vehicles use key fobs, which are remote controls that allow drivers to perform these actions from a distance. Advances in technology have led to the development of smart keys, which enable keyless entry and ignition.