Caffeine is a Firefox extension designed to prevent your computer from entering sleep mode or activating screensavers, ensuring uninterrupted usage. It operates on two levels: 'Display' prevents monitors from dimming, while 'System' keeps the entire system awake. Users can choose to maintain this state for a specified duration, ranging from 5 minutes up to 24 hours, making it ideal for tasks that require constant attention, such as downloading files.

The extension features a simple interface with an inactive toolbar button that activates the 'keep awake' mode with a single click. Users can easily switch between operating levels through a right-click context menu. When disabled, Caffeine does not interfere with the system's default power settings, providing a flexible solution for users who need to manage their computer's power-saving features effectively.