make square hole metal ISO9000:2008 Material:aluminum ,low carbon steel ,G I ,SS Technical:perforated,punching ... squrae hole metalHole punching metal :1. Hole Punching Metal Mesh Material: Low carbon steel board, stainless steel board, copper ... storage ventilation, mechanical protection5. Hole patterns of Hole Punching Metal Mesh: Round, Rectangular hole, square, Triangle, Diamond, Hexagonal, oval, ...