GSM module: SIMCOM 340DGPS module: MTKWorking method: Locate by GPS,send back the location by GSMCan't work in the room or under ground park or other indoor place that without any GPS signalThe service charge is SMS charge the longitude latitude and display the location of object on the map or satellite map Auto tracking report mode can be set up(Report every 1 minutes)Set up preset 3 phone number by SMSSMS locateLink locateOver Speed AlarmLow battery alarmMove alarm fucntion Over Area Alarm (Geo-fence Alarm)Real time track model Monitor Function Calling function SOS function Built in rechargeable Li battery (Battery Life up to 7 days) Electronic Specifications:Unit Size : 61x42x11mm- Normal Operation Temperature:-20C to +55C- Restricted Operation Temperature:-35C to +70C- Storage temperature:-40C to +80C- GSM Frequency:850/900/1800/1900 MHz- GSM & GPS Antenna:Built-in- GPS Channels:32- Locate Accuracy:5~10m- GPS Start Time (open sky):Hot Start : 1 sec, Cold Start : 36sec- Standby Current:1-2 mA - Tracking Current:35mA- Charge Voltage:5V- Battery:Li-ion 800mAh (BL-5B) Free location serveice website is ; Package list1 Main unit , 1 car recharge adapter, 1 manual. Package: gift box: 20cm X 5cm X 2.5cmPackage Dimension: 49cm*45cm*29cm Weight: 0.6kg Quantity Per Carton: 32set