… Natural rubber, balata, gutta-percha, guayule, chicle and similar natural gums, in primary forms or in plates, sheets …
Explanatory notes
… ‑ Natural rubber, balata, gutta-percha, guayule, chicle and similar natural gums, in primary forms or in plates, sheets … further, it must not contain any added carbon black, silica or any other substance of a kind forbidden by … chambers, with the latex, an inert substance, such as siliceous earth, expressly to prevent agglomeration of the …