To those who submit (presumably without ever having used one) that it’s useless, the answer is maybe. I own the first cup and the drink mug (one was a gift). It’s actually very cool to have a drink still piping hot for a long time. Caveat 1: the bottom guts take a lot of space, so the volume they can hold is less than the appearance suggests. Caveat 2: woe betide anyone who puts milk in their hot beveage. It will leave a sticky skin on top, and leave rings of dried skin on the inside of the vessel. As someone who prefers milk in his coffee, and as an occasional tea drinker, mine remain in the closet.