Introduction: This product is easy to install. Just stick the main unit on the door frame and the auxiliary unit on the door or two windows, and align the auxiliary unit arrow with the side mark of the main unit.
When someone opens the door or window illegally (the main unit and auxiliary unit are separated by more than 10mm), the alarm will emit an alarm sound of >90DB to warn the intruder to leave.
When you want to open the door or window yourself, you can control it by the switch. Use 3×1.5VLR44 (AG13) button batteries (included in the machine).