Sealed on BOTH SIDES of the bearing to keep lubricant in. Suitable for complex environment durability and resistance to deformity under heavy loads Z1 Noise Level for most general use Pre-Lubricated, Easy to maintain Deep Groove Ball Bearings are one of the most widely used rolling bearings. They are used to accommodate radial and axial loads in both directions. Suitable for all kinds of industrial equipment, Mini motor, small rotary motor, office equipment and so on. With small friction and high-limit speed,Deep Groove Ball Bearings are cost-effective and require little maintenance. better in toughness than chrome steel bearings after quenching. These cost-effective bearings are widely used in areas with low requirements for Mohs hardness. Single-row, pre-lubricated, normal accuracy. Model: 698-2RS Sealed Type: Double Sealed Heat Treatment: Quenching Hardness: HRC50-55 Accuracy Class: P0 (ABEC-1) Noise Level: Z1 Weight: 73g/set colour:Silver + black Material:Carbon steel size:Inner Diameter (d): 8mm Outer Diameter (D): 19mm Thickness (B): 6mm Package Contents: 20*Deep groove raceway bearing NOTE： Please refer to the picture and select right type of bearings before your order (Sealed or Shield on BOTH or SINGLE side of the bearing). Suffix on the bearing just for differentiating between Sealed and Shield type of bearing. It would not affect the use of our product. Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.