Yes. The chime that ends each block can be muted in the focus timer, and the block then runs and finishes silently.
Muting changes nothing else. Blocks still run their full length, completed blocks are still counted, and you still get the longer break after every fourth one. Only the sound stops.
The chime exists so you can put the phone face down and stop watching the clock. If you have to keep checking whether the block has ended, the timer is doing half a job.
In a silent room that trade goes the other way, which is why the setting exists. The usual replacement is to leave the screen visible at the edge of your desk, or to put the device on its charger where you can see it without picking it up.
Work minutes over break minutes: 15/3, 25/5, 20/10 and 50/10. There are no custom durations. A longer break arrives after every fourth completed block.
More answers on the help page, or write to [email protected].