It is a stopwatch. But with "Estimer Lite" you can estimate the final time.You can select the final distance and split, or next stop. And you can also use laps if you prefer laps.After specification is ready, you can start the run.Here is my test run!I shake my device and the clock starts running. It can be also started by touching the "Go" button, but shaking is smoother. You do not have to concentrate to your device, you can concentrate totally to the run. Hopehully you have that "shaking" available in your device!First stop is coming, shake, the time is taken. Again it is easier to take the time by shaking