Personalized Superhero 6th Birthday Pink Long Sleeve T-Shirt. Happy 6th birthday! Celebrate your child's sixth b-day with a cool SUPER 6 superhero party. Happy Birthday six-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