They don't fit.

[Hubert H]

I bought these cap-less refills thinking I could use them in pens using Ball point Parker style refills. They don't work! Can anyone tell me what pen can I use the Schmidt cap-less System P8126 in? Thanks for the help/info.

 

[Fibonacci]

That model is not one that I have used, but based on the dimensions, it looks like it should fit any of the rollerball pens (gent, zen, baron, etc.).

It looks like it is a schmitt style cartridge, not a parker style.