From the sellers website:
Get ready to set your morning ablaze when you bring home this officially licensed X-Men #1 Cover By Jim Lee 15oz Heat Changing Mug. This epic Marvel Heat Changing Mug features a classic X-Men #1 Cover By Jim Lee that changes colors when heat is applied and holds 15 ounces of your favorite morning coffee or tea! HAND WASH ONLY & NOT microwave safe **
Retails for $17.99
