Personalized Superhero 2nd Birthday Long Sleeve T-Shirt. Happy 2nd birthday! Celebrate your baby's second b-day with this cute I'm 2 super hero design. Happy Birthday two-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