| 524 / | HD | SYNTHETIC RESINS OR NATURAL RUBBERS -- PART OF THE CLASS 520 SERIES |
| 925 | DF | NATURAL RUBBER COMPOSITIONS HAVING NONREACTIVE MATERIALS (DNRM) OTHER THAN: CARBON, SILICON DIOXIDE, GLASS TITANIUM DIOXIDE, WATER, HYDROCARBON, HALOHYDROCARBON {3} |
| 926 | DF | .~ With water as NRM, exemplified {1} |
| 927 | | .~.~ Before 1930 |