The mysterious time-traveling power of the Craigh Na Dun standing stones are a secret best kept between those brave enough to make the trip. You can sneakily commemorate your temporal adventures with this special transforming mug, which reveals the symbol of the Craigh Na Dun Travelers Society when filled with the hot beverage of your choice. Cool it down again, and it's just a simple black mug. Your secret is safe! This mug transforms from black to a full color image when filled with hot liquid. This 11 Oz mug is not microwave or dishwasher safe, hand wash only.