D8 steel mesh refers to the mesh steel sheet made of steel bars with a diameter of 8mm, which does not involve the grade of steel bars, as long as it is used for ordinary concrete, regardless of rings and ribs;
D8 ribbed steel mesh refers to the mesh steel sheet made of ribbed steel bars with a nominal diameter of 8mm, regardless of the grade of ribbed steel bars, regardless of HRB335, HRB400, HRB500, etc.