It’s a mug, a thermos and a bottle. 16oz’s of durable double walled construction and vacuum insulation keeps hot drinks warm for 6 hours and cold for more than 24. 2 lids for your choice of use. 100% food grade stainless steel won’t impart or retain flavors. Go from lattes to lemonade without a problem. BPA free, toxin free. This Klean Kanteen is literally the best coffee mug in the world and probably the last one you will ever buy except to give to a friend. It’s that good.