Personalized Martial Arts Future Black Belt Karate Long Sleeve T-Shirt. Cute future black belt Long Sleeve T-Shirt - White for boys or girls interested in karate, martial arts sports. Pre-shrunk 100% cotton 6.1 ounce long sleeve t-shirt. Double-needle stitched neckline and sleeves. Quarter turned. Shoulder-to-shoulder taping. Adult: S, M, L, XL, 2XL, 3XL