Personalized Baseball 7th Birthday Long Sleeve T-Shirt. Happy 7th birthday! Celebrate your child's seventh b-day with a cool SUPER 7, superhero personalized gift. Customize and add your child's name. Happy Birthday seven-year-old! Pre-shrunk 100% cotton 6.1 ounce long sleeve t-shirt. Double-needle stitched neckline and sleeves. Quarter turned. Shoulder-to-shoulder taping. Adult: S, M, L, XL, 2XL, 3XL