The right wheels are the most crucial part of vehicles projects for kids and classes. Plastic bottle caps are too small, and CDs are difficult to attach to an axel. These project wheels are designed specifically for educators, parents, and makers who want to build vehicles that work the way you expect. The 4.75-inch wheel diameter helps your projects go the distance, and the included rubber bands improve traction so no energy is wasted due to low-friction contact with the ground. 10 dowels made to fit onto the wheels are included.