Personalized Bicycle Rocks Text Toddler T-Shirt. An image of a bike with the word rocks spelled out by happy rock critters is a funny gift design for bikers at birthdays and holidays. A toddler-soft cotton tee in look-at-me, big kid colors. 4.5 oz., 100% combed ringspun cotton. White is sewn with 100% cotton thread. Topstitched rib crew neck. Double-needle stitched sleeves and bottom hem. Shoulder-to-shoulder taping.