These sensors activate whenever a door or window is opened, and then emit a wireless signal to a central alarm system, such as our JC-G02 (which can track up to 99 wireless sensors). This sensor does not emit an audible sound that can be heard.
Place these sensors on doors or windows and they will trigger whenever the door or window is opened, and your central alarm system will then alert you when there is activity -- you can then view the area if you have surveillance cameras established, or be alert to take other action.