This two-way GSM audio device calls you when it detects sounds in its vicinity. Insert a GSM SIM card and program it to your desired phone number for call back. This device has two functions: Make a call to the audio device to instantly listen in to conversations. The built-in microphone works up to a 7 meter radius. It can also call you automatically when it detects people talking. Condition: New. Origin: China. When sound is detected, the device will call your cell phone. Recharge the audio device by connecting the USB charger cable to a power source. This product is sold as an investigative tool for law enforcement or licensed investigators. It is the customer's sole responsibility to determine if this product is legal to import and use in their country. Specifications: GSM Frequency Compatibility: Tri-band (850MHz, 900MHz, 1800MHz, 1900MHz) Microphone Range: 5-7 meter radius Power: Built In 400 mAh Rechargeable Li-ion Battery Expected continuous working time with voice control: 5-8 days Expected continuous working time with positioning only: 16-21 days Dimensions: 4.3 x 3.2 x 1.4(cm) Package Included: 1 Listener 1 Charging cable 1 Instructions