When this arrived, I frowned, thinking it's so small no way will it keep anything even mildly warm for more than 5 mins, much less hot. BUT...I tried it out, and sure enough, it will keep a full thermos of coffee HOT for hours and hours!!! Testing it without opening, it kept coffee hot enough to drink after 6 hours! So happy to have this to take to events (dog shows specifically where there is rarely any afternoon coffee available.) I do recommend this. It's small, and that's what I wanted, but know that it is mostly a one person thermos.