Great Nudes Heat Changing Coffee Mug - Add Hot Liquid and Watch the Figures Change From Prudes to Nudes - Comes in a Fun Gift Box Add a hot beverage and everyone's clothing disappears. Featuring 13 works of art from the 15th to 20th centuries. 12 oz. mug. Heat changing mugs are microwave safe, but not dishwasher safe. Hand wash only. Don't soak. Comes in a colorful box. Click on "The Unemployed Philosophers Guild" near the product title to see more great gifts. UPG truly has presents of mind.