Car Alarms - A Car Alarms is an electronic device installed in an automobile that discourages theft of the vehicle itself and/or all of its contents. Car Alarms work by making high-volume sounds, usually a siren, but also a klaxon, a pre-recorded verbal warning, the vehicle's own horn, or a combination of these, when the conditions necessary for triggering are met. It also can flash some of the vehicle's lights, and, in some cases, notifying the car's owner via a paging system and interrupting various electrical circuits necessary for the car to start. The individual triggers for a Car Alarms can widely vary, depending on the make and model of the vehicle, as well as the brand and model of the Car Alarms itself, for aftermarket Car Alarms. Since aftermarket Car Alarms are designed to be universal, which means they are compatible with all 12 volt negative ground electrical systems as opposed to one carmaker's vehicles, these commonly have trigger inputs that the installer/vehicle owner chooses not to connect, which additionally determines what will set the Car Alarms off. Because of the large number of false alarms that came with Car Alarms, many vehicle manufacturers will no longer factory fit simple noise-making Car Alarms. Instead they will offer silent, but still effective, immobilizers. Also, an aftermarket vehicle tracking system can make it possible for the police to trace stolen vehicles. Most police tracking systems require the user to pay a monthly fee, whereas factory immobilizers are included in the purchase price of the vehicle. GPS locating systems enable the owner of the vehicle to lock and unlock, disable the starter, and track the vehicle online. Other additional options allow the user to receive messages if the Car Alarms is set off or if the vehicle breaches a specified speed or boundary.