Personalized Blue Monster 1st Birthday Long Sleeve T-Shirt. A blobby blue monster holds a yellow balloon and wears a bright birthday party hat as it celebrates the one year old's 1st birthday! 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