Noorio sensors can only be installed indoors.
The product comes with a protective film. You could tear it off if it had scratches on it.
Make sure the mark on the contact sensor is aligned with the mark of its magnet component. Otherwise, the sensor may not respond to door/window open and close actions.
Install the magnet component next to the contact sensor as close as possible. However, you must check if the door/window can be open and closed as usual before the installation.
Mout Your Device
Tear off one side of the film on the 3M stickers and stick them to the sensor and magnet component respectively.
Tear off another film of the 3M stickers and stick the contact sensor and its magnet component to a door or window.