Functions and features: 1) Offer 2 RJ11 output ports to connect 2 sensor or display system. 2) Simple 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. Main parameters: 1) Size: 71 x 50 x 13mm. 2) Case: ABS. 3) Output port: 2 ports of RJ11. 4) Alarm volume: 95DB. 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: USB. Optional accessories: 1) Power adapter: 5V/4A. 2) AS3X series IR remote keys.