Basic features: Built-in GPS personal locater Supports 4-frequency: GSM 850/900/1800/1900MHz High sensitivity, new technology and latest GPS SiRF star III chipset Compact size, and smaller than one name card, easy to hide Very low power consumption Fast signal acquisition Supports single location and continuous tracking Supports defined Geo-fence exceed trigger alarm Supports alarm and remote monitor Supports quick dialing buttons for 2 preset phone numbers Supports check location by SMS and Internet Monitors can track the person without interfering him SOS button send out exact location for immediate rescue/action No monthly service charges to be paid to the call center Extend function: Built-in speaker and microphone Supports two-way conversation without ear microphone (handsfree) Built-in motion sensor for power saving Built-in motion sensor for vibration alarm Voice monitoring function (wiretapping) Removable internal battery Specifications: GSM module: Embedded GSM 900/1800/1900MHz and GPRS TCP/UDP GPS chipset: Latest GPS SiRF star III chipset GPS sensitivity: -158dB GPS frequency: L1, 1575.42MHz C/A code: 1.023MHz chip rate Channels: 20CH all-in-view tracking Position accuracy: 10m, 2D RMS Velocity accuracy: 0.1m/s Time accuracy: 1us synchronized to GPS time Default datum: WGS-84 Reacquisition: Average 0.1s Hot start: Average 1s Warm start: Average 38s Cold start: Average 42s Altitude limit: 18, 000m (60, 000 feet) maximum Velocity limit: 515m/second (1000 knots) maximum Jerk limit: 20m/sec Operating temperature: -25 to 65° C Humidity: 5 to 95% non-condensing Dimension: 76 x 44 x 20mm (13mm) Weight: 75g Voltage: Rechargeab