International Natural Rubber Type and Grade Description (RSS)

General Spec Nothing but coagulated rubber sheets, properly dried and smoked, can be used in making these grades; block, cuttings or other scrap or frothy sheets, weak, heated or burnt sheets, air-dried or smooth sheets not permissible. Slight resinous matter (rust) and slight amounts of dry mould on wrappers, bale surfaces and interior sheets, found at time of delivery will not be objected to. Oxidized spots or streaks, weak, heated and burnt are not permissible.

The rubber must be dry, firm, free of blisters. Dirty packing, sand, and all other foreign matter is not permissible
RSS 1 Each bale must be packed free of mould. There is no penetration of mould inside the bale.Small pinhead bubbles, if scattered, will not be objected to. Should "Rust" or "Dry Mould" in an appreciable extent appears less than 2.5% of the bales sampled. under-cured, over-smoked, opaque sheets are not permissible. clean, strong, sound. Free from blemishes and resinous matter (rust)
RSS 2
 Small bubbles and slight specks of bark is permissible Should "Rust" or "Dry Mould" in an appreciable extent appears less than 5% of the bales sampled. under-cured, over-smoked, opaque sheets are not permissible. clean, strong, sound and free from blemishes
RSS 3 Slight blemishes in color, small bubbles and small specks of bark is permissible Should "Rust" or "Dry Mould" in an appreciable extent appears less than 10% of the bales sampled. under-cured, over-smoked, opaque sheets are not permissible. strong and free of blemishes
RSS 4 Medium size bark particles, bubbles, translucent stains, slightly sticky and slightly over-smoked rubber are permissible Should "Rust" or "Dry Mould" in an appreciable extent appears less than 20% of the bales sampled. under-cured, over-smoked sheets are not permissible. free of blemishes
RSS 5 bubbles and specks of bark is not objected to. Should "Rust" or "Dry Mould" in an appreciable extent appears less than 30% of the bales sampled.