iBELL Gsm Home Security Alarm System with 2 Door Sensors, 1 Motion Sensor, 2 Remote & 1 Wired Siren (White) Gsm smart home alarm security system with 2 door sensors, 1 motion sensor and 1 siren. Ideal security system for home, office and shop. When sensors triggered it will make alert phone to programmed telephone numbers, and send sms messages to all programmed numbers. Attached siren will make 110 db loud siren. This unit can arm and disarm using mobile phone application