... of advanced industrial manufacturing craft and high-tech precision perforation design, with professional acoustic non woven fabric as backing ... . See perforated name as below, the common perforation and pattern.R: Globe perforation, 6mm, 8mm, 12mm, 15mm circular holesQ: ... x 3mm square holes, 3 x 3 circular holesH: Perforation layoutS: Surface coating, PVC veneer, plain, distribution patternsB ...