3dRose Keep Calm its Your 21st Birthday, Blue and White, Fun, Magic Transforming Mug, 11-Oz 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