Type: Deep groove at high speed. rolling elements: single row. internal diameter: 17mm Outer diameter: 26mm thickness: 5mm Crowd: 10 pieces. Lester: 83 grams (approx. 2.9 ounces). ). These grooved rodents are made of high quality steel for low noise and long life. Rubber seal ring The deep groove ball bearing high-speed uses ring iron cover seal to prevent pollution and save lubricating oil. The inner diameter of the bearing is 17mm, the outer diameter is 26mm, and the thickness is 5mm. They are ideal for small DIY projects with 17mm steerers/stems. There are 10 miniature bearings in total which can be used for many different projects.