3dRose Worlds Greatest Boss Gold Text on White Fun Office Gift, Magic Transforming Mug, Blue, 11-Ounce Fill with hot liquid to transform from black to white, magically revealing image White ceramic mug with black outer surface; image printed on both sides Available in 11oz only; A fun and unique way to enjoy your favorite hot beverage A perfect gift for any occasion; Fascinate them every time by revealing a secret or surprise image Microwave-safe, hand-wash to preserve image