3dRose Mug Best Engineer Ever - fun gift for engineering job - black text (mug_184996_3) - 11oz - Transforming, Black/White 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 Not microwave-safe, hand-wash to preserve image