Item: MR85CE Ball Bearing Type: Full Ceramic Ball Bearing Cage: PTFE Balls: ZrO2 zirconium oxide ceramic Inner/outer races: ZrO2 (zirconium oxide) Ceramic Dimensions: 5mm x 8mm x 2.5mm/Metric ID (inner diameter)/Bore: 5mm OD (outer diameter): 8mm Width/Height/thickness: 2.5mm Size: 5x8x2.5 mm Quantity: One Bearing