... quality 4,The materials are bearing steel Guanxian Aolong Precision Bearing ManufacturerThere are four parts of a bearing, they are:1,Inner and ... ,32300 series.MaterialsCarbon steel,Stainless steel,Chrome Steel and Bearing steel,GCr-15Seals typeOpenPrecision rating P0Vibration LevelV1Tolerance CodeABEC-1Quality ... :http://alzbearing.en.alibaba.com carbon steel high precision Taper Roller Bearing