Sorry, I just don’t get this. I got this overpriced coffee mug for Christmas and, if you ask me, it is a complete waste of good money. As an engineer I am still struggling to understand what useful purpose it is suppose to provide. I get wanting to keep your coffee or beverage hot, but it only holds about 8oz of liquid.....so, who takes that long to drink that much coffee? Now don’t get me wrong, all the bells and whistle‘s are fun to play around with, but at the end of the day I’ll stick with my Stanley Steamer that keeps 8 cups of coffee hot 6 hours after I have filled it up. Probably good for “poser” coffee drinkers who want to look serious but don’t have a clue what French press is. In my opinion, if you are a true coffee drinker this will serve no purpose but to annoy you. My “Cup of Joy”, as I named it, is “charging” on my counter now where it has been since my first use in preparation for keeping the next 8oz cup of coffee I drink heated for 4+ hours.