1、These bearings are made of high quality metal for low noise and long service life. 2、They are rubber sealed to avoid contaminants entering and save lubricant. 3、Bearings have a 8mm inner diameter, a 16mm outer diameter, and a 5mm thickness. 4、These are great for small hobby 5mm shaft/rod projects. 5、There comes total 10 pieces miniature bearings which you may use for many different projects. Features: These bearings are made of high quality metal 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 16mm outer diameter, and a 5mm thickness. These are great for small hobby 5mm shaft/rod projects. There comes total 10 pieces miniature bearings which you may use for many different projects. Specifications: Model: 688-2RS Material: Metal Type: Deep-groove high-speed Rolling Element: Single row Sealing: Rubber Seal Inner Diameter: 8mm/0.3in Outer Diameter: 16mm/0.6in Thickness: 5mm/0.2in Quantity: 10pcs Weight: 38g(approx.) Package Includes: 10 x Bearings