This ad-free, full screen timer is great for classrooms or conference presentations with its on-screen buttons. The +/- buttons adjust the time and you can PAUSE or REPEAT. The URL in your browser's address bar contains the duration of the timer. This means you can:
Bookmark Big Timer with multiple times with different durations
Link from a presentation to Big Timer with the duration you need for that item
Pause the timer and add &go=true to the URL and Big Timer will start running immediately when you open that URL next time. If you send the URL of a running timer to another computer, both computers will count down to exactly the same time.
Since it is free you may want to open the PREFERENCES and scroll to the bottom to click STOP THE TRACKING. No personal information is collected.