The paper turns into chemically. 7 Mm, Plaster, Brd, Sim'l, N/O, Paper Fa Resistance, 5 Pcs / Plaster, Brd, Sim'l, N/O, Paper Fa Regular , Pcs zero X 0 X12. Exterior gypsum soffit board will be manufactured with a type X core. http://www.onestopclean.kr/bbs/board.php?bo_table=free&wr_id=248041