Super High QualityOur bicycle auxiliary wheels are made of high quality metal, plastic and rubber materials. They are non-slip and noiseless, so your child can be safer and more stable when riding without worry or worry. Perfect Combinationthe package includes (2 shoulder bolts, 2 washers, 2 lock nuts, 2 handguard washers, 1 wrench). You can choose more height adjustment options, so the exercise bike can be installed quickly and easily. The training bike has a small bracket, which is more stable and can help young students ride a bike until they feel the balance of the bike, so you don't have to worry about your kids' safety. Wide ApplicationChildren's best friends - keep your child balanced and confident without having to wear a saddle. It will bring more entertainment for your kids. Perfect Customer ServiceIf you have any questions about our products, please email us. We will solve the problems to your satisfaction as soon as possible