... hole, square, triangle, diamond, hexagonal, cross, slotted Opening type: round, square, triangle, diamond, star etc. Material: iron sheet, ... best quality.Opening Patterns including: round, rectangular, square, triangle, diamond, hexagonal, cross, slotted and ... steel , brass steel etc.Hole patternround (generally running in diagonal rows at 60 degree), rectangular, elliptical, square, triangle, ...