Personalized Rocket 4th Birthday Toddler T-Shirt. Happy 4th Birthday! A rocket blasts off from an alien world with a giant 4 for the four year old's fourth birthday! A toddler-soft cotton tee in look-at-me, big kid colors. 4.5 oz., 100% combed ringspun cotton. White is sewn with 100% cotton thread. Topstitched rib crew neck. Double-needle stitched sleeves and bottom hem. Shoulder-to-shoulder taping.