Personalized Birthdaysaurus Rex Long Sleeve T-Shirt. Birthdaysaurus Rex - A cute, smiling T-Rex dinosaur wearing a birthday party hat and holding a cupcake. Great gift for any dino lover! 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