SYNTHETIC RUBBER NEOPRENE OR NITRITE BONDED CORK COMPOSITION SHEET GRADE RC- 50/ B FINE GRANNALS, SIZE: 600 MM X 900 MM X 3. 2 MM THICK TO IS: 4253/ 80 PART- II. THE SHEET SHALL BE DULY STAMPED BY MFR ' S NAME, MONTH, YEAR OF MANUFACTURING IN INDELIABLE INK & SUITABLY PACKED IN TRANSPARENT POLYTHENE BAGS DULY SPRINKLED WITH FRENCH CHALK POWDER INDIVIDUALLY.