A key fob is a small electronic device used to control access to a system, often found in vehicles and buildings. It typically contains a button or two that, when pressed, sends a signal to unlock doors or start an engine. Key fobs enhance security by allowing only authorized users to gain entry. Many key fobs use radio frequency identification (RFID) technology, which allows them to communicate wirelessly with a receiver. Some modern key fobs also include features like remote start, panic buttons, and even smartphone integration, making them versatile tools for convenience and safety.