Vintage Nina Herold Happy Birthday Cupcakes Mug Heat Changing 11 oz

Vintage white happy birthday mug with multicolor cupcakes around the whole cup on a black background. Artwork by Nina Herold. The lights are supposed to be heat changing but I haven’t tested this - sold as is. Holds 11 oz. Measures 3.8” H. X 4.2” W (including handle). Pre-owned in very good vintage condition, typical wear of age, no chips or cracks. Please see photos for best sense of condition.