These are the only ski goggles with a "Heads Up" performance display. The goggles use GPS and state-of-the-art sensors to track maximum, average, and current speed, current temperature, latitude and longitude, total vertical distance traversed, number of runs completed, and total ground covered. The unobtrusive 2" display is similar to those found in jet pilots' helmets--the LCD "dashboard" continuously displays performance data inside the goggles' right lens frame (does not block view) and alerts when altitude or speed milestones are achieved. A built-in stopwatch lets you time and "flag" runs for posterity. The goggles store up to 24 hours of data in internal memory that can be uploaded to a computer via the included USB cable, and with free downloadable software, organized, analyzed, and shared with family and friends. The goggles themselves feature permanent anti-fog, polarized lenses that block 99% of glare and automatically transition between yellow and deep amber as light conditions change. The GPS is powered by a Li-ion battery that lasts up to six hours on a three-hour charge via USB or the included AC adapter. Includes hard protective case and carrying bag. Software works with Windows 7, Vista, XP, and Mac. 4" H x 7" W x 4" D. (11 oz.)