Personalized Dinosaur 4th Birthday Women's V-Neck T-Shirt. A dinosaur apatosaurus (or brontosaurus to the grandparents) stands tall over the 4 for the fourth birthday. Happy 4th birthday to the four year old! 5.0 oz., 100% pre-shrunk cotton Athletic Heather is 90/10 cotton/polyester 1x1 rib collar with mitered v-neck Shoulder-to-shoulder taping Ladies' fit