The eTrex Vista combines a base map of North and South America, with a barometric altimeter and electronic compass. The compass provides bearing information while you're standing still and the altimeter determines your precise altitude. The Vista is also designed to provide precise GPS positioning using correction data obtained from the Wide Area Augmentation System (WAAS). This product will provide position accuracy to less than three meters when receiving WAAS corrections.The eTrex Vista also boasts an internal memory capacity of 24 megabytes, which allows it to accept downloaded mapping data from Garmin's MapSource CD-ROMs, including Fishing Hot Spots. A silver case gives this unit a high-tech look. New to the product design, Garmin will include marine aids to navigation in addition to the base map. These navigational aids can be pre-loaded into each unit from the factory. more info