... , while backup battery fully charged state, can retain data for 4 hours, to prevent accidental data loss and other power5. Extend ... with LED flashExpansionInternal GPS:Channel 48,Accuracy 2.5m,In motion 0.01m/sExpansionInternal HF RFID Read WriteExpansionInternal Wireless Communication module GSM/GPRS,Support GSM/GPRS ...