Speed and distance powered by GPS give you the freedom to run off the beaten track. You just start running, the run trainer tells you how far, how fast and how intensely you are on the go. After the run, the performance and the route covered can be evaluated online. large, adjustable display shows the required information at a glance in 3 or 4 lines 5 ATM test pressure (GPS, HRM and ANT + function not available when under water) Performance and route data downloads via online training software powered by Training Peaks easy setting of all user parameters via desktop software - upload and download - Timex Device Agent Compatible with Windows XP or higher and Mac OS X Snow Leopard 10.6 or higher Please also note the T5K575. This model also contains a chest strap for heart rate measurement.