NR: Natural rubber obtained from the latex of tree Hevea Brasiliensis, native of Brazil and grown in tropical region of globe 15º on either side of equator. South America, West Africa Malaysia, Thailand, Sri Lanka and India are major producers of NR.
Ribbed smoke sheets(RSS) taken out of smoke house are visually examined by holding against clear light & graded as RSS1X, RSS-1,RSS-2,RSS-3,RSS-4 & RSS-5 depending on the colour, translucency, bubbles, blisters, dirt, sand and other foreign matter. In general RSS sheet should be dry, clean, strong sound, evenly smoked, reasonably free from blemishes specks, sand, resinous matter & dirty packing, small pin head bubbles, if scattered, should not be objected to.