Features: 1. It has smooth operation, low running noise and high running speed. 2. The contact between the roller and the guide rail is two 60-degree contact, and has good contacting performance. 3. The running resistance is small, so that it has long service life 4. The internal structure design of the double row angular contact ball bearing and the thickened outer ring make the roller have higher bearing capacity. 5. It is made of high quality stainless bearing steel, heat treated and accuracy ground. Specification: Condition: 100% Brand New Model: LFR50/5-4B Material: Stainless Bearing Steel AISI440(9Cr18) Inner Diameter: Approx. 5mm / 0.2in Outer Diameter: Approx. 17mm / 0.7in Thickness: Approx. 8mm / 0.3in Package List: 1 * Groove Track Roller Bearing Package List 1It has smooth operation, low running noise and high running speed. 2The contact between the roller and the guide rail is two 60-degree contact, and has good contacting performance. 3The running resistance is small, so that it has long service life 4The internal structure design of the double row angular contact ball bearing and the thickened outer ring make the roller have higher bearing capacity. 5It is made of high quality stainless bearing steel, heat treated and accuracy ground.