Personalized 4th Birthday Party 4 Year Old Boy Long Sleeve T-Shirt. Childs cute four year old birthday design has bear riding a bicycle with hooray Im four quote. 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