This thermos impressively maintains the piping hot temperature of my coffee or tea for 6-8 hours. I once left it at work overnight and to my surprise my coffee was still warm the next day. It retains heat so effectively that I've unintentionally burned my tongue a few times, so I recommend opening the lid for about 30 minutes before taking a sip. What's particularly great is the rubber stopper lid which allows me to add cream and sugar to my coffee and then vigorously shake it to mix everything together. The best part is it doesn't leak at all. Plus I really like the sleek design.