1. The specification values are not the same, and the specification deviation (nominal diameter, diameter, oval, etc.) of products with strong precision grade is lower than the standard value of products with low precision grade; 

2. The demand value of rotational accuracy is not the same. The rotational accuracy of products with strong precision grade (internal radial runout, outer diameter runout, the end should deal with the vibration of raceway, etc.) is stricter than the standard value of products with low precision grade;

3. The specified value of surface shape surface quality is not the same. The surface shape surface quality of products with strong precision grade (surface roughness of raceway or section, ring deviation, groove deviation, etc.) is stricter than that of products with low precision grade;

4. The raw materials of the products with higher precision grade will be more beneficial than the material properties of the products with general precision grade.