... ventilation.2)The main products is also called punch plate, perforated plate, perforated plate, mine screen, screen machine.2.Features1)Rugged, ... thickness at the aperture3.specification1)It is punched, sieve-plate thickness is generally 5-10mm;2)The aperture is ... 3mm.3)materials:low carbon steel, stainless steel plate, galvanized plate.4)Sieve-shaped with round hole, square hole, diamond hole, ...