Filter using timers

I would like to use timers as filters, but have no idea how to do it. With regular date fields I get options such as "After" and "Before" with a dropdown of times, whereas with timer, I just get a regular input field where I have to type... something.

How does it work? What do I type in there? Is it possible to add a filter that returns every record with a timer starting/ending at a specified hour, ignoring it's duration?