S61902-2RS ABEC-3 Stainless Steel Ball Bearing, it has Ceramic Balls (Si3N4 Silicon Nitride), each bearing has 2 Rubber Seals to protect the bearing from dust or any possible contamination, also bearing is pre-lubricated with grease.

• Item: S61902-2RS Ball Bearing
• Type: Deep Groove Radial Ball Bearing
• Size: 15mm x 28mm x 7mm
• Inner Diameter: 15mm
• Outer Diameter: 28mm
• Width: 7mm
• Closures: Rubber Seals
• Material: Stainless Steel
• Lubrication: Self Lubricated (Grease)
• Balls: Si3N4 Ceramic (Silicon Nitride)
• Quantity: One Bearing