Features: These bearings are made of high quality steel for low noise and long service life. They are rubber sealed to avoid contaminants entering and save lubricant. Bearings have a 8mm inner diameter, a 19mm outer diameter, and a 6mm thickness. These are great for small hobby 8mm shaft/rod projects. There comes total 20 pieces miniature bearings which you may use for many different projects. Specification: Model: 698RS Material: Bearing steel Type: Deep-groove high-speed Rolling Element: Single row Inner Diameter: 8mm / 0.3in Outer Diameter: 19mm / 0.7in Thickness: 6mm / 0.2in Quantity: 20pcs Weight: 145g / 5.1oz(approx.) Package list: 20 * Bearings Package List 1These bearings are made of high quality steel for low noise and long service life. 2They are rubber sealed to avoid contaminants entering and save lubricant. 3Bearings have a 8mm inner diameter, a 19mm outer diameter, and a 6mm thickness. 4These are great for small hobby 8mm shaft/rod projects. 5There comes total 20 pieces miniature bearings which you may use for many different projects.