61904-2RS (6904 2RS) Deep Grooved Ball Bearing / Thin Section Bike Bearing - Sealed SKF 20x37x9

61904-2RS (6904 2RS) Sealed Thin Section Bike Bearing - Metric 20x37x9 - SKF Premium Quality

Deep Groove Ball Bearings are the most common bearing type found in a wide variety of applications. Versatile and robust they are available in a wide range of sizes and options including seals, shields and special clearance for high speed applications. The main types are:

• Open - Bearing without seals or shields, suitable for applications where lubricant will constantly flow through them i.e. gearboxes.
  
• Metal Shields (ZZ, 2Z) - Bearings fitted with steel shields and lubricated for life.
  
• Rubber Seals (2RS, 2RSR, 2RSH) - Bearings fitted with steel reinforced rubber contact seals which provide a better seal but add friction so are unsuitable for high speed applications, lubricated for life.