Personalized My Daddy Runs Half Marathon T-Shirt. Cute half marathon running outfit for son or daughter T-Shirt - Black with my Daddy runs 13.1 quote Wardrobe essential for looking good, 24/7. 5.0 oz., pre-shrunk 100% cotton. Seamless 1x1 rib collar. Shoulder-to-shoulder taping. Double-needle stitched sleeves, bottom hem and front neck. Note: greys are a cotton/polyester blend.