Item: R188 CE Structure: Deep Groove Material: ZrO2 Ceramic Bore Dia (d):6.35 mm Outer Dia (D): 12.7 mm Width (B): 4.763 mm Closures: / Lubrication: / Magnetic: little Hardness: 58HRC Corrosion Resistance: General Clearance: C0 Grades: ABEC-7