Personalized Underestimate Old Man Longboard Long Sleeve T-Shirt. Funny retired surfer Long Sleeve T-Shirt - Black with surfboard. Never Underestimate An Old Man On A Longboard. Great gag birthday or retirement gift. 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