Synthetic Rubber Nitrile Bonded cork Com [ Synthetic Rubber Nitrile Bonded cork Composition sheet GR. RC70- A Type C fine granules size 900 +/- 15 mm x 600 +/- 10mm x6. 35 mm thick conforming to IS 4253 ( Part 2 ): 2008 Amendment No. 1 October 2010. Sheet to be stamped with manufacturer s name, month and year of Mfg. in Ink & packed in polythene bag duly sprinkled with chalk powder individually. ]