For Christmas I recieved a Thermos coffee mug. It holds 16 ounces of hot or cold drinks. I used it extensively on the fishing trip I just took with Papa and I can tell you even with the air temps below freezing the coffee stayed hot for 8 hours. Jon will testify to that. It's like having a insulated thermos in a smaller size. I really like it. Another thing I like about it is when your in a boat there is no handle to catch the flyline, an important feature if you want to avoid frustration. I do not know the cost. Here is a pic of what it looks like.