11 Ounce-Funny Novelty Funny Math Geek Mug, Holy Shift the Asymptotoe on that Mother Function Color Changing Mug Morphing Coffee Mug Cup - Great Gift Item for Anyone/Christmas/Birthday Holds 11 Ounce Magic Heat Sensitive: Just plain black in color when it's cold,mug will turn white and reveal Design only when filled with a hot beverage New design, novelty, funny Sturdy and durable Awesome Gift Idea