Ember’s new temperature-controlled tumbler is its biggest and most expensive mug yet

The Tumbler is a 16-ounce black travel mug that claims to keep your beverage at exactly the temperature you want it for hours at a time. It comes with two lids — a twist-off one with a handle and a slidingone with a mouthpiece. The battery lasts three hours, and you charge it by placing the Tumler on its charger.