Bakelite artillery spare charge containers. These would have been used for the 8 cm mortar and other pieces. Price is for one. They do have a rather noticeable Bakelite smell when opened.
These lack the normal embossing on the lid and the design is slightly different from the standard embossed type but they are clearly the same basic container. The lid and base are even interchangeable with the embossed type containers, see pictures. I am not sure if this was a late war generic variant or something for the civilian market based on the same container.
These are new old stock and come from the original roll. All are in good condition.