BT-5721 Bluetooth GPS 44-Channel Satellite Receiver (White) BT-5721 Bluetooth GPS 44-Channel Satellite Receiver (Unitraq International Co.) General Features: White design Compatible with Bluetooth serial port profile (SPP) 44 parallel satellite-tracking channels for fast acquisition and reacquisition Support NMEA0183 V3.01 data protocol Up to 8 hours of operation with internal 1000 mAh Lithium-polymer battery