General description Miniature bearings are made of high-quality steel and ceramic, designed for low noise and long life. These 608 bearings are specifically engineered for roller skating, enhancing speed and performance. The use of lighter ceramic balls allows the bearings to spin faster while consuming less energy to maintain their speed. Technical specifications Inner Diameter: 8mm / 0.31 inch Outer Diameter: 22mm / 0.86 inch Thickness: 7mm / 0.27 inch Color: Black + White Material: Mixed materials Package Contents: 80 * Bearings Measurement allowed error: +/- 1-3 cm