gsm sms tracker -GSM Quad Band 850/900/1800/1900MHZ - GSM listen function, - Positioning tracking function - SOS function gsm sms tracker Main function1,the first one,real four frequency GSM/AGPS universal tracking device2,AGPS/GPRS track,location SMS including longitude, latitude and address information.also have maps site URL3,can be switch language,chinese/enghish4,Vibration sensor alarm5, ...