Columbus V-900 Bluetooth GPS Data Logger (microSD , Voice Tag for POI, Driverless, Push to Log, 25 millions waypoints*, XP/Vista/ Linux/Mac OSX Compatible) 51 channels MTK chipset with enhanced positioning system technology (up to 1.5m accuracy with EPS Technology Voice-Tag function with built-in microphone allows adding live voice labels to any waypoint MicroSD Slot with support up to 2GB* capacity (about 25,000,000 waypoints, more than 2 years) *NOTE: 1GB microSD card is optional in the package Push-To-Log (POI anchor key) enables you to mark a POI at any time Unique SPY mode allows continuous standby logging of more than one month