Its a roller for aluminium tubes eg. tomato-concentrate or mustard.
It works good, just put the end in the roller - roll it one time with your fingers, then just press it on the table and spin it. You can pull the roller easily out afterwards (or put it back in if you need to roll it more).
there is one 65mm Version and one 45mm version. Its not ideal for elastic tubes!
Printed in PLA wiht 80% infill without support (and reduced first layer speed).