​Flanged Bearing Part Number:F688ZZ Single row flanged deep groove ball bearing - Shielded(Metric Series Ball Bearing) F688ZZ Flanged Ball Bearing,is made of Chrome Steel, the bearing is metal shielded from both sides. It has an 8mm inner diameter, a 16mm outer diameter, a 5mm thickness, and an 18mm flange. Ball bearings of this size are nice and ideal for very precision work and applications...