1. This alarm is to install a sensor on the window or door. If you open the door or window, it will trigger the alarm,and make a loud siren sound, and send a text message through the app to inform you. If you put the SIM card in the alert, it will call you the voice call. 2. If you do not have , you can put the SIM card in the alarm and open the SIM SMS function. When the alarm occurs, the alarm will send a alarm and call you voice calls to send a text message notification to your mobile phone. When triggering the alarm, you can speak to the thief or the people at home through the alarm, and you can hear them when they speak. 3. If the PIR movement sensor is installed in the need, it is the infrared sensor of the human body. When someone approaches, it will send a warning voice, and it will also send text messages and call you. 4. It has multiple setting modes, you can set it as home mode when you are at home, and set the outing mode when you go out, etc. 5. No matter where you are, you can remotely arm, disarm, set arming functions, etc. to escort your home.