Chrome steel, high quality bearing 6900 series Especially 6905 open bearing we produced more low vibration, long service life 1. Brand name: BUC2. Model: Deep Groove Ball Bearing 6900 Series3. Material: Chrome steel4. Number of row: single5. Cage: brass, cold-rolled steel, nylon6. Type of seals: open, ZZ, 2RS7. Precision grade: P0, P6, P58. Vibration level: Z1V1,Z2 V2,Z3V39. Hardness: 61 to 64 ...