Personalized Funny Mountain Biking Gravity Joke Long Sleeve T-Shirt. This cycling design for someone who enjoys mountain biking has bike and mountains silhouette and gravity joke. 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