It is a countdown timer that can count "only" 30 minutes.
There is no support for small movements such as when the app is moved to the background.
The background is gray during the countdown, but as time passes, the color will gradually change from the top.
When the countdown is over, it will turn red, so press the refresh button and count again for 30 minutes.
I think it can be used for work as well.
Please be careful as there is no alarm sound.