Personalized T-Rex 1st Birthday Youth T-Shirt. A cute little T-Rex dinosaur is smiling and wearing a birthday hat as it sits with its 1st birthday cake. Adorable gift for your one year old! 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.