I use it to transport sterilized hot water for preparing powdered milk for my 2-month-old babies. Up to the 5-6 hours that I have tested it, it keeps the water hot as it was when I put it before leaving home. If I happen to use it for a longer period of time, I will update my review.

A more accurate rating would be 4.5/5.
It is quite high-quality, closes well, and retains heat.

Attention: To drink, you must pour it into the lid first, as the valve it has has holes all around (for air intake), and if you try to drink directly, you will get dirty!