The Garmin Etrex 20 is a price-friendly unit that is heavy on the features. This handheld unit comes standard with a worldwide basemap and holds 2000 waypoint capacity, allowing you to mark your favorite hunting, hiking and fishing spots. 1.7 GB internal memory gives you storage for extra maps and images, while the MicroSD card slot allows you to load a variety of custom maps. Geocaching just got a lot easier as well, with paperless caching. This allows you to have up to the minute information such as location, terrain, difficulty, hints and descriptions. Gone are the days of manually typing in coordinates and printouts. The electronic compass features a 3-axis design, compensating for tilt and helping you see where you are going, even while standing still. The barometric altimeter helps this unit track your precise location, using changes in barometric pressure. This feature also allows you to keep an eye on ever-changing weather conditions by tracking barometric pressures over time. You'll never have to worry about wet weather ruining your unit. With its weatherproof design, the GPSMAP 62 will stay dry and functional and is submersible up to 1 meter for 30 minutes. The Etrex 10is best powered by lithium AA batteries and has an approximate runtime of 25 hours on one set. This handy little unit also features hunt/fish calendars, tide tables (with optional Bluechart map) and sun/moon information, to give you the best data for your hikes, hunts and fishing trips. The WAAS-enabled GPS receiver and HotFix satellite prediction ensures that your reception stays strong and your location and navigation is spot on. Working side by side with this technology GPS and GLONASS satellites provide faster positioning. The Etrex 10 can also be connected to a computer with Internet to connect to Garmin Connect. This handy feature allows you to track your activities and routes and share via Facebook and Twitter. The Etrex 30 is capable of wirelessly sharing tracks, routes, waypoint and geocaches with other compatible devices. Auto-routing capability allows you to easily navigate while traveling with optional City Navigator NT map data.