Those were of plain canvas, similar to rucksack's, 32x22 cm bags, supplied with white cotton drawstring through metal rings punched through canvas at the opening. Plus little coloured cloth sewn on to easily identify content.
Here's the example of replica taken from one ebay auction:
My questions for other fellow GJ with larger knowledge:
- is the sizing and looks correct ? any evidence on period photos ?
- what is the meaning of colours ? is it like red (rot) for hygiene items, blue (blau) for shoes, yellow (gelb) for food ? any rationale ?