1:The dimension requirement value is different, the dimension deviation of the product with high precision level is much smaller than that of the product with low precision level.

2: The required value of rotation precision is not the same, the rotation precision of the products with high precision is much stricter than that of the products with low precision.

3: The required value of surface shape and surface quality is different, the surface shape and surface quality of products     with high precision level are much stricter than those with low precision level.

4: The raw material requirement of the product and processing technology and factory inspection standard are also   different.

5: Product quality control, market recognition and bargaining power are also different.

6: It is very important to select the right bearing quality for the right use.