Personalized Grandpa Claus Youth Long Sleeve T-Shirt. Cute GRANDPA CLAUS Youth Long Sleeve T-Shirt - White with Santa cap is perfect for all Santa's helpers that are granddads, grand pops, poppas and papas. youth long sleeve t-shirt. Shoulder-to-shoulder taping. Youth: S(6/8), M(10/12), L(14/16), XL(18/20)