Usage Tips:Universal Compatibility: Designed to fit most children's glider bikes, training bicycle, and balance bikes with an 12 inch wheel size, ensuring a versatile replacement option Reinforced Nylon Hubs: These hubs are sturdy and long last, ensuring they won't easily break even with extended use Quiet Design: Engineered for silent operations, these wheels significantly reduce rolling noise, providing a smoother and more comfortable riding experience for your child Easy Installation: Replace the wheels in just a few simple steps without the need for professional tools, making it convenient for parents to handle on their own Complete Set: Comes as a pair of balance bike replacement wheels, great for refreshing or upgrading your child's ride with ease Specification: Material: Metal Plastic Size Chart: Diameter: 30cm/11.81inch Width: 4.5cm/1.77inch Package Includes: 1 Pair Balance Bike Replacement Wheels Note: Please allow slightly errors 1-2cm/0.39-0.79inch differences due to manual measurement.