it's a secondary door lock actuator that is hooked to a solid bar and wired to the alarm just like the door locks, if you do this ( I might as it's a decent idea) then make sure when your alarm looses power ( battery is disconnected) the door locks don't automatically unlock. Some older cars with factory power locks would do this, but I don't know if the newer cars with factory power would or if the alarms put out the unlock signal if power is cut via a lockout preventative capacitor.