Review via - 27th May, 2019 Found this fabulous deal and went with it because I've been wanting a large vacuum flask for quite some time. It was delivered promptly, however as others have noted, it has dents in the cap. While I don't consider the cap the most vital part of the flask, I don't understand how impossible it is to deliver a metal flask in an intact manner. And this was collected in store, not sent to my house. I have tested it out and it does perform well in terms of heat keeping. I only use vacuum flasks for hot water, and this kept a full bottle 'burn your mouth' hot for over 12 hours. Have not tested outside in low temperatures though, I would expect a shorter span.