Fill up on coffee or other hot beverages with the Fred and Friends TANK UP Coffee Mug. This mug comes one to a package. The mug is made of smooth porcelain. Fill this mug with the hot beverage of your choice and watch the gauge climb all the way to the full mark. The tank indicator on the side is activated by heat. Each mug is packaged in a colorful gift box, so it makes a great gift as well.