Best insulated cup I have ever used. The coffee I put in stays hot for several hours. I left the hot/just finished black coffee in the Thermos and left it in a my kitchen for 24 hours (by accident) and when I returned I tested it to see how it did. The coffee was at the "still hot, but not scorching my tounge" level. Needless to say, I was impressed. I tested it again in the car, same scalding hot coffee but this time in 30 degree temperatures. It was still above like warm after 8 hours.