Amazing thermal retention. Excellent one hand release lid, and you get a decent mouthful from it when drinking. The only flaw, is that once you use this as a coffee flask, you are committed to it being a coffee flask forever. I have tried several solutions including bio-carb and vinegar but the lid and flask always smell like coffee now. So I cant use it for water. But if you use this as a coffee travel mug -you cannot go wrong.