Features: Crafted from steel, these bearings ensuring minimal wear, and superior deformation resistance under heavy loads. Provide high and uniform hardness to resist deformation under heavy loads. Adopting rubber seals to prevent lubricants and contaminants from entering. Suitable for various devices such as roller skates, strollers, wheelchairs, to enhances the user experience and efficiency. deeply grooves ball bearings with uniform hardness distribution, engineered for seamless integration into professional skating gear and mechanical systems. Specifications: Component: Steel Size: about 22x8mm/0.87x0.32inch Package Includes: 10Pcs deeply grooves Ball Bearings note: Please allow 1-2cm errors due to manual measurement, make sure that you do not mind before you order. Due to the difference between different monitors, the picture may not reflect the actual color of the item.