Bought it from Doc. We only used it a couple times though...I should test it out again. The cup is huge and holds a lot. Cant remember what I put in it at the time, but it didn't have ice and the drink got warm. So, it needs to be a beverage that takes ice, and won't taste bad if ice melts.... so probably strong lemonaide or an iced mocha or something.
Note-- this was also during summer, so not only was the tub 101, the outside temp was probably 95 too.