Size: 6204-2RS (Inner Dia.=20mm, Outer Dia.=47mm, Thickness=14mm) Material: CNXBB Ball Bearing is made of premium bearing steel not carbon steel. High speed operation, high temperature resistance, low noise and smooth rotation. These brand new bearings come directly from factory and fully tested. Widely Application: Motor, power tools, automobile, household appliances and others. Excellent Performance : Precise and versatile, performing well in noise and vibration detection. Pre-lubricated with grease, less friction, no maintenance needed. Satisfaction Customer Service: If you're unsatisfied or have an issue with this bearing, please feel free to contact us, we will offer you a satisfactory solution！ bearing