Did you once lie on the living room floor, eating cereal and watching flintstones? Now you’re all grown up and just do grown-up things. One of the best parts of growing up? Coffee. And there’s no reason you can’t have grown up coffee in a flintstones mug. The exterior of this officially licensed 11 oz. mug transforms from black as hot liquid is added, revealing the hidden image in full vivid colors. While this mug may be used in the dishwasher or microwave, for the longest-lasting, highest quality product, we strongly recommend against it. Please do not microwave this mug. Hand washes only. Due to the need for the hot liquid to transform the mug, this mug might not be suitable for young children.