Suitable: Universal training wheels are suitable of Children's single-speed bicycles for 12/ 14/ 16/ 18/ 20/ inch , however it is not for certain models of HUFFY bicycles.Material: high-quality ABS wheels and high-quality steel, lightweight and noiseless. which will be safer and more stable for beginners.Easy to instal: All mounting hardware is included, you will have more choices to adjust the height at any time according to the skills and levels of the trainee.