A car alarm is a security device designed to deter theft and protect vehicles. It typically consists of sensors that detect unauthorized entry or movement, triggering a loud siren or alarm sound. Many modern car alarms also include features like remote keyless entry and GPS tracking, enhancing vehicle security. When a car alarm is activated, it can alert the owner and nearby individuals to potential theft. Some systems can send notifications to a smartphone, allowing the owner to respond quickly. Overall, car alarms serve as an important tool in preventing vehicle theft and ensuring safety for car owners.