MR633ZZ Chrome Steel Ball Bearing 3mm x 13mm x 5mm MR633ZZ Ball Bearing, Bearings are made of Chrome Steel, each bearing has 2 metal shields to protect the bearing from dust or any possible contamination, also bearings are pre-lubricated with greaseItem: MR633ZZ Ball Bearing Type: Deep Groove Ball Bearing Style: MR Metric Size Material: Chrome Steel Closures: Metal shielded (Both sides) Dimensions: 3mm x 13mm x 5mm Inner Diameter: 3mmOuter Diameter: 13mmWidth: 5mmDynamic load rating Cr: 1,300 NStatic load rating Cor: 490 NLimiting Speed: Grease Lubrication: 44000 RPMQuantity: One Bearing