The 7.75-inch sub-assemblies
Currently I am using some surplus green outside carpeting, but the cavity it fills is by design. The carpet maybe replaced with different tooling, sheets, grids, whatever.
The bottom (black) and the top (white) snap together, and the pair weighs 17 grams. Three of then needed for the full 24" segment, which is 51 grams, takes about 6-7 hours to print on one printer. Compared to molded plastic this is still very expensive, because of the electricity and opportunity time (printer utilization). When deployed a broken segment is going to take this much resources to be re-printed.