Features: Help your child learn to ride a Bikes with these PU Flashs Wheel. They usings magnetic Flashs, not require batteries. These Wheel is make of Carbon steel stand, ensuring durability and long terms use. The nonslide and quiet feature offer a smooth and secure experience. Suitable for childrens who is learning to ride, these Wheel is perfect for improvings balance and control. Suitable for various outdoor setting, make learning to ride a Bikes a fun and enjoy experience. They great for home use but also suitable for schools and Bikes club. Specifications: Materials: Carbon steel stand Size: 12inch/14inch/16inch/18inch/20inch 12inch applicable rear wheel radius: about 15.0cm/5.90inch 14inch applicable rear wheel radius: about 17.50cm/6.89inch 16inch applicable rear wheel radius: about 20cm/7.87inch 18inch applicable rear wheel radius: about 22.50cm/8.86inch 20inch applicable rear wheel radius: about 25.0cm/9.84inch Package Includes: 1pair Bikes Auxiliary Wheel note: Please allow 1-2cm errors due to manual measurement, make surely that you not mind before order. Due to difference between different monitors, the picture may not reflect the actual color.