This two way GSM audio device calls you when it detects sounds around . How is that? Simply insert a GSM and it to your phone number for call back and now you're in the business! You can even place several of these audio devices and set up at your locations like the bedroom, living room, conference room or office. Just insert a into the audio device and your bug is active and for action!This two-way audio device comes with two functions:(1) Make a call to the audio device and you can instantly listen in to conversations! The built-in microphone works up to a 7 meter radius, so set this bug up wherever you !(2) Allows the audio device to call you when it hears people talking! This feature makes it much more advanced than other GSM audio bugs on the market today.Hot spots: Audio Gadget, Auto Dialing option, -Band GSM Audio DeviceProduct Notes :When it detects sound, will call your cell phoneYou can recharge the audio device by connecting the USB charger cable to the power chargerThis product is being sold as an investigative tools for enforcement or licensed investigators.Specifications:Primary Function: -band GSM Two-Way Audio DeviceMaterials: PlasticColor: as shownGSM Frequency Compatibility: -band (850MHz,900MHz, 1800MHz, 1900MHz)Microphone Range: 5-7 meter radiusPower: Built In 400 mAh Rechargeable - BatteryTurn on control function and the expected continuous working time is 5-8Only the positioning function is expected to last for 16-21Dimensions: 4.3x 3.2 x 1.4(cm)Package Contents:1 x Locator1 x Charging cableOnly the above package content, other products are not included.Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.