Grade A Brightness is 90% and above. CaO levels are less than 10%. Grade B Brightness is in between 85 % and 90%. CaO levels are less than 5%. Grade C Brightness is in between 80% and 85%. CaO levels are less than 3%. Grade D Brightness is in between 75% and 80%. CaO levels are less than 2%. Grade E Brightness is in between 70% and 75%. CaO levels are less than 2%. Note that we can produce various mesh sizes on condition that we do have sufficient quantity of order every month.