1、Carbon Steel Material: Made of high quality carbon steel, high hardness, heavy bearing capacity, smooth surface and corrosion resistance. 2、ABEC 9 Bearing: Using ABEC 9 standard specification bearings, high accuracy, low noise, uniform speed during high efficiency operation. 3、Good Performance: 608RS ABEC 9 bearing has stable performance, good coordination with machinery, and improved work efficiency. 4、Wide Range of Application: 608RS ball bearing can be used for twisting cars, roller skates, dance boards, skateboards, etc. 5、Wear Resistant: Bearing are resistant to wear during high speed operation. Metal cover sealed to prevent the entry of impurities. 8 x Bearing Item Type: 608RS Ball BearingMaterial: Carbon SteelInner Diameter: Approx. 8mm / 0.31inOuter Diameter: Approx. 22mm / 0.9inThickness: Approx. 7mm / 0.28inWeight: Approx. 92g / 3.2oz