Personalized Big Sister Superhero Long Sleeve T-Shirt. I'm the big sister, and I'm a superhero! Cool gift for any super big sis! 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