【PREMIUM MATERIAL】Ball bearings are made of high quality carbon steel with super hardness and load bearing capacity and smooth surface. 【PRECISION STANDARD】Following the ABEC 9 precision grade standard ensures the bearings' high precision, low noise and even speed in efficient operation. 【STABLE PERFORMANCE】608RS ABEC 9 bearings run smoothly and work well with all kinds of machinery and equipment, effectively improving work efficiency. 【WEAR-RESISTANT】Skate bearings are able to resist wear and tear at high speeds, and the metal cap sealing design prevents the entry of impurities and prolongs service life. 【APPLICATIONS】Roller skate is suitable for a wide range of equipment, such as twisting cars, roller skates, dance boards, skateboards, etc., to meet the needs of different equipment. <br> Specification: Item Type: 608RS Ball Bearing Material: Carbon Steel Inner Diameter: Approx. 8mm / 0.31in Outer Diameter: Approx. 22mm / 0.9in Thickness: Approx. 7mm / 0.28in Weight: Approx. 92g / 3.2oz <br> Packing List: 8 x Bearing <br> Note: Please allow 1‑3mm error due to manual measurement. Thanks for your understanding.</p>