Cello Lifestyle 500 Ml Flask (Silver) A Cello Flask is known for its heat resistance property means water or any liquid remains at the same temperature for a longer time. Hot water or coffee will remain hot for the significantly extended time. Utilizing this property, it works magically in the summer season. You can carry cold water anywhere in your Cello flask. The water will remain cold. There is no better thing than quenching the thirst with cold water in summer, especially when you are out of your sweet home. More to it, you can get your name on it to make it more personal.