1These bearings are made of high quality steel for low noise and long service life. 2They are double shielded to avoid contaminants entering and save lubricant. 3There are several different types and sizes of bearing that you can choose as needed. 4These are great for small hobby projects, suitable for both professionals and enthusiasts. 5There comes total 10 pieces bearings which you may use for many different projects.Features: These bearings are made of high quality steel for low noise and long service life. They are double shielded to avoid contaminants entering and save lubricant. There are several different types and sizes of bearing that you can choose as needed. These are great for small hobby projects, suitable for both professionals andenthusiasts. There comes total 10 pieces bearings which you may use for many different projects. Specification: Model(Optional) Inner Diameter Outer Diameter Thickness 607-ZZ 7mm / 0.3in 19mm / 0.7in 6mm / 0.2in 608-ZZ 8mm / 0.3in 22mm / 0.9in 7mm / 0.3in 609-ZZ 9mm / 0.4in 24mm / 0.9in 7mm / 0.3in Cage material: Steel plate Type: Deep-groove high-speed Usage: Universal Rolling Element: Single row steel balls Bearing Material: Bearing steel Angle: 15 degree Sealing: Double shielded Quantity: 10pcs Package list: 10 * Bearings