Magellan eXplorist 400 Water Resistant Hiking GPS Unlimited SD Card Expandability - Your eXplorist 400 features SD card compatibility for unlimited memory expansion. USB data port - Transfer map data from your PC to your eXplorist 400 with the high-speed USB data port. TrueFix GPS technology takes advantage of 14 parallel channels, supported by WAAS and EGNOS Satellite-Based Augmentaion Systems Built-in mapping - With 8 MB of built-in North American or European maps it's easy to navigate around roads, parks, waterways Easy-to-use - One-button access takes you directly to all of the most important features. Intuitive operation with keypad