The Polar RS800sd Running Computer is a complete system for planning, monitoring and analyzing your training. It provides an optimum combination of features for elite level athletes and their coaches. With the new Polar WearLink transmitter W.I.N.D., the Polar RS800sd™ is part of the world's first integrated training system together with adidas running gear. It also comes with the new Polar s3 stride sensor W.I.N.D. for detailed speed/pace and distance tracking, and is compatible with Polar G3 GPS Sensor W.