What a 75 minutes timer is good for
A longer bake, a nap that covers a full sleep cycle, a parking meter, or a long study session with the sound set to something gentle.
The countdown runs against your device clock, so it stays accurate if the tab is throttled in the background. At zero it fills the screen with a Stop button, plays your chosen sound, and vibrates on phones. Prefer a clock time instead? Use wake me up in 1 hour 15 minutes.