Personalized Greatest Grandpa T-Shirt. World's Greatest Grandpa T-Shirt - White gift has vintage style logo on a Father's Day or new Grandpa gift for him in blue and tan. 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.