This children bike wheel is made of iron and rubber material, stable and sturdy, it is safe and durable, not easy to deform and break. Made with fine workmanship, make it easy to install. Besides, designed with luminous design, your children will like this when they are bike. Features -Color:Black -Material:Rubber, iron -Size:11.00X11.00X2.00cm/4.32X4.32X0.79in -Application: Compatible with 12 inch, 14 inch, 16 inch, 18 inch, 20 inch bike -This bike wheel assist learners until they have developed a usable sense of balance on the bikes. -The wheels can ensure your child's safety and prevent accidental injuries when learning to ride. -Anti-slip, wear resistant, providing stability and help children to ride a bike without - , iron support can provide extra stability and safety, suitable for bikes with a size of 12-20 inches. -Professional design, beautiful appearance, with luminous function, much cool for your children. Package list: 2 x shoulder bolts 2 2 x vertical brackets 2 x washers 2 x nuts 2 x spacers 1 x wrench