The running-clock principle does what it should, is beautifully light and easy to use. However, a GPS sensor seems to be built, which was maybe 10 years ago, state of the art. While current Android, IOS or Navi Geraäte are able to determine the current position within seconds after switching on the GPS receiver, the Forerunner 10 is required for getting well over a minute. The attached manual is just adequate, the Internet sites of Garmin Connect pretty confusing. You have to look forever or consult the FAQ, until one finally finds the settings so that you can change from Miles to km etc., although it is set to the clock as a German. Due to the lame GPS and the lack of adaptation to Europe this Running Watch is IMHO recommended only conditionally.