Dual phase Pomodoro-style timer. Set how many minutes you would like to work, follow that with a rest period, then repeat. Drag the timer measurement bar horizontally to adjust times. Press the microphone icon to use your voice to set the timer. For example: "set timer for 3 and a half minutes" or simply the number of minutes like "10".
Demo: https://yankidank.github.io/Pomodoro-Timer/
Available as a web app or Chrome Extension.