When young children start to ride a bike, the they need to gain is a sense of balance. Our wheels are an additional wheel mounted parallel to the rear wheel of a bike, which sure your child is safe when learning to ride. Provide children with more self-confidence and let them learn to ride a bike when they is safe to improve their learning efficiency. 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 -Sturdy and durable, it can help the bike beginner to keep balance and overcome the -Our safety wheel allows your child to relax while riding without worrying about falling or scratching. -This bike wheel includes complete install accessories and make it easy to install. -Wear-resistant, provide stability, help children ride bikes, and let children enjoy the fun of riding bikes. -Creative glowing bike wheels, which children bike and attractive. Package list: 2 x shoulder bolts 2 2 x vertical brackets 2 x washers 2 x nuts 2 x spacers 1 x wrench