| 428 / | HD | STOCK MATERIAL OR MISCELLANEOUS ARTICLES |
| 221 | DF | WEB OR SHEET CONTAINING STRUCTURALLY DEFINED ELEMENT OR COMPONENT {9} |
| 304.4 | DF | .~ Composite having voids in a component (e.g., porous, cellular, etc.) {14} |
| 318.4 | DF | .~.~ With nonvoid component of specified composition {3} |
| 319.3 | DF | .~.~.~ Synthetic resin or natural rubbers {1} |
| 319.7 | DF | .~.~.~.~ Linear or thermoplastic {1} |
| 319.9 | | .~.~.~.~.~ Hydrocarbon polymer |