Description:  Open the door , trigger the door sensor , and turn on the light at home by the linkage switch .    Feature :   - Real time monitor:  When the door / window is opened or closed , an instant notification will be pushed to your mobile phone immediately . So you don't have to worry about your baby going out without notice . It is easy to know when your elderly parents leave or arrive home , even when someone enters your home , store , office , etc. at a glance .  - 24/7 monitor:  Provide 24-hour monitoring . Even if you are far away from home , garage , garden , etc. you can check whether the door / window is open anytime and anywhere through the app .  - Loud Alarm:  When someone opens or closes your door or window , a loud alarm will be triggered to keep you informed .  - APP remote control:  Support viewing open / close records in the application . Don't worry about missing any important moments . If you have installed multiple door sensors in different places . All the status of doors and windows will be displayed synchronously in the APP , allowing you to see at a glance .  - Low battery reminder:  When the battery power is low , it will automatically remind you to replace the battery , so you don't have to worry about running out .  - Share with your family:  Share the added door sensors with your family , they can also monitor the status of your doors and windows when you are out .    Note :  The wifi door sensor we sell is the latest model , with linkage mode .  1. It can be set to automatically turn on the light after opening the door sensor .  2. You can also set to automatically turn on any other smart life equipment after opening the door sensor . Connect to the router without a gateway .    Specification:  Application / Platform : Tuya / Smart Life App;  Operating system support : IOS8.0/Android4.0 and above;  Wi-Fi frequency band : 2.4 GHz / 2.4 GHz and 5GHz;  Battery : AAA * 2 batteries ( not included );  Wireless distance : up to 50 meters ( open area );  Detection distance : ≤15mm;  Working temperature : - 10 ℃ ~ + 40 ℃-;  Working humidity : up to 95% RH;  Dimensions :  ( main body ) : 70mm x 25mm x 20mm;  ( small body ) : 35mm x 10mm x 17mm;    Package Include:  Window and door sensor x 1