Fifteen different species of beautiful butterflies and moths change to reveal their brilliant colors. Printed on both sides of mug. Wondermugs are color-changing coffee mugs that change dramatically when a hot beverage is added. If you're looking for a unique and romantic gift for her, what a unique way to remind him or her of your love daily! These unique, high quality gift mugs utilize color-changing or “thermochromatic” ink that changes color when hot beverages are poured into the inside of the mug. Color change gift mugs are ideal for fund raisers, birthday gifts, teacher's gifts, corporate gifts and more. All mugs are microwavable. We recommend hand wash only (no soak) to preserve the magic ink.