Recently, there has been a surge in the popularity of Yeti cups (and their copy cats). They're remarkable because they keep hot beverages hot, and cold beverages cold for a long time in spite of the temp of the room/ car. A fellow sales rep left her Yeti cup in the car for around 12 hours in the hot summer sun, and when she opened it, the cup still had ice in it!
The cups are made of cast aluminum, and have some sort of insulation in between the walls of aluminum- seems simple? But, should we be drinking from these day in and day out?
Please advise.
http://yeti.com/rambler-30/