Window Alarm, 10-Pack Wireless Window Door Entry Alarm Burglar Security Alarm Magnetic Sensor Ideal for Home, Garage, Apartment, Dorm, Office

I have not installed them yet, but I tried one. They are decently loud. They are very sensitive, so they need to be lined to right. If you have a loose door, they might be to sensitive. But for a window or a door that does not move, they will work just like an alarm type. I am going to put them on all the doors and windows which already have alarms, but it will be just another siren at the point of entry, if needed. And is you leave some windows slightly open in good weather, it would go off if the window moves.