"Keep splashes and sloshes at bay and debris and spray out with the Rambler® MagSlider? Lid. Magnets offer a smoother and more reliable sliding mechanism - plus it's simple to remove for easier, more thorough cleaning. While the magnet adds an additional barrier of protection for keeping coffee or water contained and preventing heat or cold from escaping, please note - this magnet component is not leakproof and will not prevent spills."