8x13 Bearing 8x13x4 - Shielded - Miniature8 x 13 x 4 Shielded Ball Bearing One Bearing 8 x 13 x 4 Shielded Ball Bearing,made from durable 52100 alloy steel, commonly known as chrome steel, each Comes with double metal shields (ZZ) to keep out dust and dirt,plus its pre lubricated with grease so its ready to roll right away. 8 x 13 x 4 Ball Bearing Deep Groove Ball Bearing Dimensions: 8mm x 13mm x 4mm Metric ID (inner diameter) Bore: 8mm OD (outer diameter): 13mm Width: 4mm Size: 8 x 13 x 4 mm