Paddlers and boaters will appreciate the Garmin GPS Map 78's highly sensitive receiver as well as the floatable housing and stable rubber side grips. With a WS enabled GPS and HotFix satellite prediction, the GPS Map 78 locates your position quickly and maintains your location in deep canyons. USB computer compatibility lets you download detailed marine, topographic, road, and hiking maps for versatile adventures. There's a built in memory with 1. 7GB of space, and Garmin added a slot for your own microSD memory card. Dual battery system accepts two standard batteries, lithium, or NiHM battery packs.