Usage Tips: Wear-resistant, thickened wheel design. Bicycle training wheels are made of high-quality plastic and rubber. Includes everything needed to install wheels on a bicycle with 18-22 inch wheels. Safety: Our bicycle wheels are made of high-quality metal, plastic materials, and rubber. They are non-slip and noiseless, allowing your child to ride more safely and smoothly. Good stability: The sturdy wheel rear wheel stand provides excellent support for children to maintain safety and stability during the first test drive. It offers the best start for your child to achieve balance and stability, building confidence for riding with two wheels. Easy to install. Suitable for bicycles with 18-22 inch wheels.