TFA HiTrax Tip Handbuch Seite 28

11.1 Using the Timer Mode
To Use the Timer Mode
Once a target time has been set (for example 30 minutes), press
the [start/stop] button once to start the countdown. The countdown
time will be displayed continuously throughout the countdown.
To stop countdown, press the [start/stop] button once.
To Reset the Timer
To reset the timer to the preset target time before the countdown
reaches zero, press the [reset] button once (when the timer has
stopped counting).
To start the counter at a target time, set a new value for the target
time. Check the previous '11.1 Setting the Timer Mode' Section for
more detail on how to set the Timer Mode.
Timer Alarm Sound
When the timer nears the last 5 seconds, the watch will beep once
for each second left. When it hits zero, the watch will beep for about
10 seconds
You can stop the beeping by pressing any button (except the [light]
button).