Personalized 4th Birthday Monster Truck Women's V-Neck T-Shirt. I'm Four! A red monster truck drives over the words. Great fourth birthday gift for your favorite 4 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