I've eyedroppered a few packs' worth of these by now. Most notably, I eyedroppered one about 8 months ago, and filled it with Whaleman's Sepia. I carried the pen daily, commuting on helicopters to work in offshore oil equipment maintenance. It never burped, it never leaked. It was bulletproof.
One day it went missing. "Oh well," I thought, "It's just a Preppy. Hope someone has a good time with it."
Fast forward four months. My mom sees something sticking out of the seal in her washing machine. It's my Preppy. Still full of Whaleman's Sepia, exactly the quantity I left it with, still writing just as nicely as the day I lost it. The only evidence anything had even happened was a little ink inside the cap from being vigorously shaken about for a third of a year. Somehow, the pen hand ended up in her washer (and I don't live there). There, it had stayed, cycle after cycle, for four months, enduring hot, cold, immersion, agitation, and Lord knows what else.
I don't know of any pen, let alone eyedropper conversion, that I would expect to survive that. This did. These O-rings work.
