Bad Elf 2300 Bluetooth GPS+GLONASS Receiver and Data Logger with Barometric Altimeter High performance Bluetooth GPS+GLONASS WAAS Receiver accurate to 2.5m enhances the utility of your iPad, iPhone, or iPod touch without an internet connection or monthly subscription. Adds barometric altitude for pilots and raw barometer readings for boaters with the built-in digital barometric sensor. Advanced USB connectivity allows streaming of NMEA data directly to a PC or Mac. Adds easy access to recorded data logs (up to 200 hours worth of storage) just like a thumb drive 24 hour battery frees your iPad, iPhone, and iPod touch form carrying the power burden of determining your position. High performance Bluetooth GPS+GLONASS Receiver accurate to 2.5m enhances utility of your iPad, iPhone, or iPod touch without an internet connection or monthly subscription.