... B with Memory and Sleep Function. Specification:1) Communication with GSM/GPRS, GSM frequency 4-band 850/900/1800/1900, can be used ... memeory 1MB(16,000 positions) for storage and upload when GSM/GPRS offline and optional 2GB external SD card at most.3 ... the tracker.16) State checking function: can check state of GSM, GPS, GPRS and battery.17) Double 3.7v, 1000mA Li-batteries ...