This vintage coffee mug from Spencer Gifts is the perfect humorous gift for someone celebrating their 40th birthday. Made of ceramic and porcelain, it features the phrase "I Must Be 40" in bold letters, with a colorful design that adds to the fun. This mug is sure to bring a smile to anyone's face and is perfect for coffee, tea, or any other beverage.

The mug's unique design and high-quality construction make it a great addition to any collection of dinnerware and serveware. Made in Indonesia, this mug is both durable and dishwasher safe, making it easy to clean and maintain. Overall, this Spencer Gifts coffee mug is a great way to add some humor and personality to any coffee break or mealtime.