TSNR (400122) is graded by technical properties such as dirt content, ash, and plasticity retention index, and is typically sold in baled block form. Smoked sheets (400121) are visually graded ribbed or crepe sheets dried over smoke. The processing method and grading standard determine which subheading applies, not the end use.

No. Guayule and similar non-Hevea natural gums fall under 400130 alongside balata, gutta-percha, and chicle, while Hevea-derived natural rubber in latex or solid primary forms falls under 400110 through 400129 depending on form and processing.