This is the best travel mug I have ever used. I mostly left it uncapped (mostly) but it kept my tea HOT for a long time. I underestimated it and burned the crap out of my tongue when taking a sip. Towards the end it was warm but still a good drinking temperature. That was over a period of 6-7 hours. The design includes an infuser basket that attaches to a strainer. The infuser basket is detachable. Underneath the lid is an extra compartment where you can store extra loose tea. I didn’t have any issues with the those tea leaves getting moist or anything for the time I had the cap on (close to an hour).