If you mean a device that is a stylus at one end and a pen at the other - I have (and like) the Kensington Virtuoso stylus/pen combo. I got it for about $20 (USD) at
Amazon.
It is a good length for a stylus (about 5" long) and with the pen, it's a bit heavier than most. This I like. The cap, with a clip, fits over the pen and then it pulls right off to use the pen. The only bad thing about that is that you cannot put the cap over the stylus end, should you wish to use the pen for any length of time. I don't, so it doesn't bother me - but it does make it shorter as a pen...
The stylus works well and I like it. It's the same kind of tip as the Targus or Boxwave stylus - that hollow rubber kind.
That's the only pen/stylus I've got/used. I know there are others. Good luck with your search.
Marilyn