... , the feed, the dustgrinding machine sieve, the jig, the labor character to sieve, the kitchen equipment uses the stainless ... carbon steel, galvanized, brass, copper and plastic.Shape of holesRound, Square, Rectangle, Triangle, Fish-scale, Diamond, Hexagon, Cross, Obround ... but it is the worst compression hole of the series.Square holeSquare hole punching perforated metal mesh provide greater porosity ...