A GSM listening bug inside a desktop calculator, with all the standard features. The professional device with highly sensitive sensor allows to start the bug when it detects a sound or a movement.
Fully functional Desk top calculator has GSM listening device with 40 hours operation. This fully functional calculator can be left in office without arouse any suspicious and you will know what is happening when you are away. You can charge the battery via USB port of your computer or USB mains charger.
It's very easy using it: it's enough insert the SIM card into the slot and the device is ready. So you can put the device in a hidden place which you want monitor. Dialing the SIM card number, you can hear all is happening around the device.