Synthetic Rubber Nitrile bonded cork com [ Synthetic Rubber Nitrile bonded cork composition sheet grade RC70- A Type C fine granules size 900 mm +/- 15 mm x 600 mm +/- 10 mm x 4. 8 mm thick conforming to IS 4253 ( Part 2 ): 2008 Amendment No. 1 October 2010. The sheets shall be duly stamped with manufacturer s name & date of manufacture in indelible ink and suitably packed in transparent polythene bags duly sprinkled with chalk powder individually. ]