Wayfair is carrying the highest quality thermos I have been able to find anywhere:  Zojirushi - the vacuum insulated one.  In my search for a thermos that would hold my drink temperature for more than an hour or two, I have bought and comparison tested many of them for 6 hours, and returned all of them except the best of the bunch, a Yeti.  One returned was a non-vacuum insulated Zojirushi.  The Yeti lasts a few hours and is bulky and doesn't have a flip top so I checked Zojirushi on Wayfair as you have quite a few of them.  I also wanted one that I liked to look at and spotted cobalt blue, but mainly I discovered that the more expensive Zojirushis are vacuum insulated so I bought it.   This thermos is fantastic - cold drinks for 4-6 hours! and still drinkable overnight.  All the others started tasting suspiciously after 6 hours.  It even seems to hold up in hot weather but I drink it too quickly to test it.  THANKS