Here is a Very Specific Object. For one of the nine people in the world who own a Pilot Down Force pen (I already excluded myself from the total), here’s a direct fit replacement clip for when yours breaks.
Who cares, and why? Well, part of this pen’s deal is that the clip is absolutely required to use it. That’s because the angled rib on the clip is part of the hold-open mechanism. No clip, no write.
And now, no problem.
https://www.printables.com/model/768071-pilot-down-force-replacement-clip
It’s twofold. That’s half of it. The other half is there’s a piston in the clicker button that pressurizes air against the ink in the cartridge so it’ll do all the usual writes-upside-down-in-space-underwater malarkey. Only without the need for specialized pressurized cartridge.
Having the hold-open on the clip, separated from the pressurizer, probably immensely simplifies the mechanical design. And probably ironically makes it stronger.
(And I carry my pen that way all the time.)
Thats actually pretty cool