Personalized Farty Forty Youth T-Shirt. You're farty! I mean forty. Happy birthday, you old fart. Funny gift for your favorite 40 year old's flatulent 40th bday. Let the good times roll in a durable T-Shirt that takes kids from school to play in an amazing array of colors. 5.0 oz., pre-shrunk 100% cotton. Seamless 1x1 rib collar.