The polar m400 gps is a sleek looking high tech sports watch great for supporting and enhancing your training and performance the built in gps tracks your pace distance calories and altitude and will give you a route back to your starting position it is water resistant up to 30m and can save up to 30 hours of training information which can be synced with other devices and used with the polar flow mobile app and web service so that you can analyse your workouts and set goals and targets it