Timer expiration behaviour
From the "Advanced" tab you can choose how the timer will behave when the expiration occurs.
This option will show a static timer image with zeros:
Show Expiration Message
Alternatively, you can show a custom message which is displayed when the countdown is over:
Reset and Restart
This mode is applicable to evergreen timers (e.g. "Run when email is opened" and "Run when email is sent").
As the title suggests, this will create an endless timer.
Use case example: set the timer duration to 24 hours and automatically restart everyday at 11 a.m.
Finally, this option will convert your timer into a 1x1 pixel invisible image.