Functions and features: 1) Offer 1 RJ11 output port to connect 1 sensor or display system. 2) Simple and small appearance design, LED indication function to show work condition of every defense area. 3) Built-in rechargeable lithium battery with 7 days standby time in maximum, low battery indication function. 4) Alarm will be triggered when alarm unit is detached. 5) Code modification function. 6) Offer power switch. 7) Built-in short-circuit protection function. Main parameters: 1) Size: 45 x 45 x 12mm. 2) Case: ABS. 3) Output port: 1 port of RJ11. 4) Alarm volume: 100DB. 5) Standby time of built-in rechargeable lithium battery: 7 days. 6) Code modification function: yes. 7) Low battery indication: yes. 8) External power on / off indication: yes. 9) Power input port: MINI USB. Optional accessories: 1) Power adapter: 5V/2A. 2) AS3X series IR remote keys.