This self-cooling tumbler keeps beverages cool for long even in very high temperatures. For the cooling effect to start, the tumbler simply needs to be soaked in water for a minute. The unglazed and porous outer surface of the tumbler absorbs the water and the evaporation process cools it for hours. The tumbler is also dishwasher safe and, thanks to its shape, suitable for different beers. Additionally, its outer surface can be marked by using chalk.