Personalized Super Trex 5th Birthday Youth Long Sleeve T-Shirt. Rawr! A Trex superhero wearing a birthday hat is surrounded by a colorful burst of confetti. Cool 5th birthday gift for your five year old. youth long sleeve t-shirt. Shoulder-to-shoulder taping. Youth: S(6/8), M(10/12), L(14/16), XL(18/20)