As others have said the bottles keep drinks Nice and cold for a long time. Can't say how they perform when keeping things hot, but judging how they handle the cold drinks, I'd say that they'll do very well. One thing I am very impressed with is the customer service, thanks Ronan. When our first bottle arrived and it had a dent I contacted Ronan and he sorted out a replacement within a few hours, despite the fact it was the weekend. He was a pleasure to deal with and for that alone I'd use the site again. So overall highly recommended and at a price that you're unlikely to better elsewhere on the net.