Functions： (1) The most advanced GPS module in the world； (2) Works worldwide! Support 3 or 4-frequency：GSM 850/900/1800/1900 MHZ； (3)Two way for data transfer： SMS，GPRS； (4)Real time tracking； (5) SOS button send out exact location for immediate rescue/action； (6) Independent SOS button which will send GPS information via SMS to 1 preset cell phone number or send alarm to monitor center (7)Continual location reporting (8) Parameter is setted via SMS (9) Low battery notification before the battery runs out! (10) Speed limit alarm (11) Alarm when belt is being loosened or being cut illegally Technical parameter： GSM/GPRS: (1) GSM Antenna：Built in (2) Protocol: Support TCP transmission GPS: (1)GPS Antenna：Built in (2) Accuracy：1-5m Electronic: (1) Operating Voltage：3.4-4.5V (2) Charge voltage：4.5~5V (3) Standby：10mA (4) Operating：80mA (5)Battery Li-ion：650mAh (6) Stand-by time：48 hours Package: (1) Main Part Size： 50mm*36mm*15mm