For boaters and watersports enthusiasts who want to run with the best, the rugged GPSMAP 78 features crisp color mapping, high-sensitivity receiver, new molded rubber side grips, plus a microSD card slot for loading additional maps. And it floats! The GPSMAP 78S has a built-in 3-axis tilt-compensated electronic compass, which shows your heading even when you’re standing still, without holding it level. Its barometric altimeter tracks changes in pressure to pinpoint your precise altitude, and you can even use it to plot barometric pressure over time to keep an eye on changing weather conditions. Wt: 7.7 oz.