Perforated Copper Part Number             Hole size           Pitch              % Open area               Sheet size                  Thickness STAINLESS STEEL 304 STAINLESS STEEL 316 BRASS MILD STEEL ALUMINIUM              30C                1.75mm             2.62mm             41                    1.22M x 0.40M              0.70mm                  53C                3.00mm             5.00mm             33                        2M x 1M                    0.70mm                70C                3.18mm             4.98mm             37                    1.22M x 0.61M              0.90mm                85C                5.00mm             8.00mm             35                        2M x !M                     0.70mm