Color Morphing Mug, 11ozPersonalized mugs are super popular gifts for friends and loved ones. This one changes color and will be the gift that keeps on giving. The heat reactive surface reveals your custom designs once the mug gets warm. The ceramic cup will go back to its original black outside and white inside when it cools down. The C shaped handle helps keep a sturdy grip. It comes in one size 11oz (0. 33l) plenty for that big morning cup of coffee. .: One size: 11oz (0.