Personalized Monster Truck 7th Birthday Youth Long Sleeve T-Shirt. Monster truck 7th birthday! A monster truck drives through the frosting on a cupcake, splashing it around in a giant mess. Cool gift for the birthday kid! youth long sleeve t-shirt. Shoulder-to-shoulder taping. Youth: S(6/8), M(10/12), L(14/16), XL(18/20)