I am the (once proud, but not longer) owner of an array of Rotring Artpens.
After finally running out of my stash of ink cartridges I ordered a batch of new ones from Rotring.
Said cartridges now are shorter by 1mm, with the result that my ArtPens now rattle when I write if I carry a spare ink cartridge.
I could of course 'fix' the problem by stuffing some paper in there, but... eh. I just feel like my entire kit has been vandalised, why not just charge me a few pennies more and sell quality items instead of junk?
From the Rotring home page:
"Technical pens, mechanical pencils, calligraphy pens:
Premium performance tools which enable thinking and creativity with
--- if you can put up with the rattle that is!