This I posted on Facebook and told friends at work. If you see an advert for for an item called Chilly (Flask) read it and if interested buy it. I purchased one 750ml and it does what it says, I filled with fridge cold water this morning about 10am and I have just finished the last drop if fridge cold water. I even left the flask out in sunlight and the water was still fridge cold. My opinion worth the money and I am not easily swayed buy claims made by companies. But happly this does what the label says. I'm impressed and I'm liking, going to take it to the Philipines with me and try it there next week I can recommend this Chilly Bottle and I would recommend this Chilly bottle.