One Ball Bearing R4-2RS and are made of Chrome Steel, this  bearing are sealed with rubber seals to protect the bearing from dust or any possible contamination, these are self lubricated bearings (bearings are already greased).

• Item: R4-2RS
• Closures: 2 Rubber Seals
• Quantity: One Bearing.
• Material: Chrome Steel
• Quality: Electric Motor Quality
• Bearing dimensions: 1/4" x 5/8" x .196"
• Inner Diameter: 1/4"
• Outer Diameter: 5/8"
• Width: .196"