High quality control,Size: (300) 600 x 600 (1200/1800), 595 ... : 7mm-15mm Difference Lighweight mineral fiber acoustic boardMineral fiber board( high density)1Raw materialnewsprint (recycling oldNewspapers) recycling ceiling (recovered older ceiling), expanded ... 732usd No such size of ordinary one. And based the high desity, so it will need more more raw material. Therefore ...