Feature:Wear-resistant thickened wheel hub design: The bicycle drive wheel is made of high quality plastic and rubber. Auxiliary wheel size is adjustable, suitable for bikes about 12-20 inch. Sr, non-slip, silent: High quality ABS casters and high quality steel support arms. Our wheel support arms are 3.0mm thick, which means increased safety and stability. They are non-slip and quiet, so your child can be safer and more stable when riding without worry. Easy to install: The package includes 2 plastic auxiliary wheels, 2 screws, 2 nuts, 2 washers and 2 fixing nuts. You have more options to adjust the height, so you can easily quickly install the auxiliary wheels on the bike. Good performance: : The sturdy rear wheel support wheel can provide the security and stability required for the first test drive. Letting kids drive with more confidence is the best place to start trusting kids. Guarantee: If you have any questions about this product, please contact us by email, we will get back to you within 24 hours. If the purchased product has any quality defects, we offer a 60-day money back guarantee or.