Personalized Worlds Best Grandaddy Youth T-Shirt. Fun Grandaddy Fathers Day Youth T-Shirt - White gift for him has blue and white logo for your grandpa. Also makes a great birthday gift for him. 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.