The 25000 is from "JOST" and was their largest size production; 150 x 100 mm...

The carton pieces were part of a series -- 160 x 110 mm for the 100.000 and 150 x 100 for the 50.000 -- and they were made in the same exact (exactly) manner as was a 33rpm phonograph record jacket; and probably way before the 33's even existed. Unfortunately, we have no idea why they exist or their purpose...

I had a few of each (25000, 50.000 and 100.000) which were placed many years ago; except for one or two examples that will be available in the not-too-far-off future... The 1000 is the rarest of the lot and presented to me as a gift (serial number 1)... of which I never had any dupes.