Personalized Worlds Best Trombone Player Youth Long Sleeve T-Shirt. Cool trombone player gift has Worlds Best trombone saying in two tone sports style design and comes on this fun trombone Youth Long Sleeve T-Shirt - White gift for your trombonist in marching band or jazz groups. youth long sleeve t-shirt. Shoulder-to-shoulder taping. Youth: S(6/8), M(10/12), L(14/16), XL(18/20)