639 Full Ceramic Ball Bearing, the inner diameter is 9mm, outer diameter is 30mm and the width is 10mm, this is a popular size that could be used in many applications, Bearing is made of Ceramic.

• Item: 639 Ball Bearing
• Type: Full Ceramic Ball Bearing
• Cage: PTFE
• Balls: Si3N4 Ceramic (Silicon Nitride)
• Inner/outer races: Si3N4 Ceramic (Silicon Nitride)
• Dimensions: 9mm x 30mm x 10mm/Metric
• ID (inner diameter)/Bore: 9mm
• OD (outer diameter): 30mm
• Width/Height/thickness: 10mm
• Size: 8x28x9
• Quantity: 20 Bearings