The Anti-Theft Alarm System includes a horn, independent of your car's power supply, and a timer-controlled alarm. This alarm is triggered if an unauthorised person tries to open the car door. It sounds the horn for 30 seconds, accompanied by continuous flashing of the hazard warning lights. The Anti-Theft Alarm uses an ultrasonic interior monitor to protect the doors, boot, engine compartment and car interior against unauthorised access. The ultrasonic system also detects anyone trying to enter the car through a broken window. It can be disabled if you have to leave your pet in the car for a short time, for example. Locking the car activates the Anti-Theft Alarm, and unlocking deactivates it.