So, I've always had this pen lying around my parents' home, and I've always have seen it there. It's a metal housing, it hasn't got any branding or markings (even though, they could have been removed).

It's a 4 in 1 style, and it seems from the seventies... Still, since we don't have any markings in the pen, we might rely on the details. Thus, here are details of the clip, the top lid, the sides of it and the... nipples? (English isn't my first language...) who pull each of the four colors out.

That pen hasn't had got any ink since a long time ago, and yet it's at home, so somebody around my family might consider it has some value, or at least, sentimental value.

Also, I've done some investigations aside:

* Most of the markings from the refills have been removed. Still, the blue one says "Hauser". Even though this doesn't mean that the pen is a Hauser, the pen might still be a Hauser (even though they are now Indian and all of that stuff).
* I've done some investigation using AI, before having to use the "organic intelligence", and Gemini says it could be either a Hauser or a Schneider from the late 60s - or even 70s, because they both often made white labeled pens.
   * I believe that the pen could have been labeled somewhere a long time ago, and the markings could have been removed due to usage, both of those possibilities could be true...
   * Gemin also said that the refills are D1 sized, so I could buy a bunch of them and bring the pen back to life, which is awesome. The pen looks hecking cool!

So... Good luck I guess!

Here you've got another vintage pen to find the model from!