Personalized Baseball 6th Birthday Youth T-Shirt. Baseball league sports style 6th birthday boy with baseball bats. Cute sports themed 6-year-old b-day party gifts. Happy Birthday six-year-old! 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.