Pap pens, as far as I know, are made by one company in Japan, Kiyota.  They
come in
several colors, clear, red and blue, and with different widths.  I think
they are
in the midst of doing some more development of newer pens.  The  colors tend
to bleed into solvents (red!) and often do not stay on Plus charge slides
(lift off,
plus some other problems) We have a hydrophobic barrier slide with Plus charge
 our specifications, design made for our lab by Erie, for use with frozen
section IHC,  and
very happy with it, it may be refined later.

Hopefully, a newer better Pap pen is on its way to market, until then you
can purchase them from
Shandon, Vector, Newcomer Supply.  They are pricey, but many people swear
by them, and I
love them when they stay on the slide for our application.  There was
discussion about the pros
and cons of these pens earlier this summer, on Histonet.

Good luck,
Gayle Callis