Gives you reminders by little beep noises, reminding you to look away from the screen to promote good eye health. The noise will beep once every 20 minutes, and after 20 seconds will beep 3 times again to signal that you have rested your eyes enough. It has been advised that you should look at an object (not a screen) which is about 20 feet away for 20 seconds every 20 minutes while working at computer screens. This extension is to help you remember to do that. Use the popup icon to turn on/off.