Personalized Cycling Environment Earth Day Bike T-Shirt. Bike more saying comes on a T-Shirt - White for Earth Day or anyone who wants to live a greener life by riding a bicycle 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.