This funny heat changing mug transforms right before your eyes when hot liquids are added! Heat sensitive mug changes color to show your own personal "battery level." Your caffeinated liquid refuel will have you going from empty to full power in no time. Black ceramic mug with copper top and white writing on it to look like a battery. Makes a unique addition to any office or wfh desk. Mug holds 10.5 ounces of your favorite hot or cold beverage. Packaged in a box perfect for gifting! Mug is not dishwasher or microwave safe.