pen for Ketubah?

hmm, i just found this on the internets:

The Jewish marriage contract should be signed with a non-smearing pen. Do not use a felt tip or fountain pen. An old-fashioned ballpoint is permanent and works very well on almost any paper. You can also get a micron uniball pen from the art store that is pigment ink, fadeproof and waterproof. These are not expensive and are readily available.


now i gotta find out what the eff a 'micron uniball pen' is