Car fobs contain panic buttons, and can double as a great alarm in case of emergency. Pressing the panic button will cause your vehicle to repetitively blast its horn and flash its headlights – if your car is in the driveway this can draw attention to your location and (hopefully) scare would-be-criminals away. Police responding to a call may find your home faster as well. Of course, if you live in a high-rise apartment, or otherwise do not store your car somewhere where it can serve as an alert mechanism, the key-fob alarm is not likely going to provide this benefit. Also, consider storing your keyfob wrapped in aluminum foil – some cars can be broken into using devices that boost and relay signals from remote keyfobs; wrapping a fob in aluminum foil when it is not in use can protect against such crimes.