DESC: Rugged, lightweight Edge attaches easily to the stem or handlebars of your bike with the included bike mount. Just turn it on, acquire GPS satellites and go. Edge 305 automatically measures your speed, distance, time, calories burned, altitude, climb and descent, and also records the route you have taken for review. For extra-precise climb and descent data, Edge 305 also incorporates a barometric altimeter to pinpoint changes in elevation.