Personalized Race Car 5th Birthday Youth T-Shirt. Start your engines! Fun 5th birthday racing car helmet, pistons, and checkered flags. Perfect for the five year old's birthday party. Let the good times roll in a durable T-Shirt that takes kids from school to play in an amazing array of colors. 5.0 oz., pre-shrunk 100% cotton. Seamless 1x1 rib collar.