Added to the original features of the Crux II, there is now a removable and rechargeable Li-ion battery, Data logger function, capable of storing 24,000 data records, and Multi-Link capability. BTGPS II Trine is a superb GPS receiver for most mobile location-awareness applications. When used in combination with the mobile host device and appropriate navigation software, a reliable navigation system will be at your disposal. Just place the small GPS receiver in the top of your rucksack, on the dashboard, on-board your boat or anywhere within 10 meters and it will transmit your current position via Bluetooth to your PDA or SmartPhone, leaving your expansion slots available for other uses.