Specifications: Sirf star iii high performance and low power consumption chipset 20 channel all-in-view tracking channels for fast acquisition and reacquisition. Compatible with bluetooth devices with serial port profile (spp). Built-in rechargeable lithium ion battery without external power supply for about 3 hours of use in connection/10 hours in scan mode Built-in rechargeable battery for memory and rtc backup and for fast time to first fix (ttff). Support nmea0183 v2.2 data protocol or sirf binary code. Flash based program memory. New software revisions upgradeable through serial interface. Provide expand terminal and can contact to other system without bluetooth devices.