... 2. ISO9001:2000 3. High Speed ZV2 Grade 4. Prices:$0.198~198/ Electric Motor Ball Bearings 6308 2RS ZV21. ... material:chrome steel2. ISO9001:2000 certificate3. High Speed ZV2 GRADE4. Inseparable design5 ... MaterialStainless steel-440C,304 316 ,Chrome steel-GCr15, high Carbon steel-GCR11Cages Materialsteel ,brassID size10-380mmQuality standardISO9001: ...