Isosteel VA 9553QAT flask 1.0 L, 18/8 stainless steel, Quickstop Einhandausgießsystem, cup and handle, titanium gray (household goods)
I have the bottle to use for about 3 weeks in daily. The insulation properties are truly outstanding, even half-filled the Soaked remains many hours hot (not warm). Provided they are flushed before the actual fill with hot water, which you should do