Finally, a ceramic-lined travel mug that caters to all of your senses and practicalities. The Carter Mug… -fits most cup holders -fits most single serve manual brew methods for easy brew n’ go. -retains heat for up to 12 hours and stays cool for up to 24 hours. -is leakproof! So while you’re out on the move, you can throw it in your bag or elsewhere without hesitation. This thing seriously keeps coffee hot all day and cold beverages cold fooooorever(well about 24 hours)! We've tried so many travel mugs and this beats them all hands down.