Personalized 4th Birthday Monster Truck Women's V-Neck T-Shirt. 4th Birthday Monster Truck Women's V-Neck T-Shirt - Aqua is perfect for the truck themed birthday party for your 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