The barrels of some of my preppys tend to unscrew while I’m writing, but if I put an o ring at the end of the barrel, it stops the problem. Also, after some time the caps of my plaisirs got a bit loose (is an aesthetic issue, because the seal still works perfectly fine), but if I put one of this o rings at the end of the barrel, the cap is always tight and even looks better. I’m very happy with the buying experience: I was surprised by how quickly my order arrived and how good the customer service was: they were always there to offer advice and to answer in no time in case there were any problems with the delivery.

Always a good product from goulet.pens. Tell Jessica and everybody I said hello.

Phillerup Speer,🧑‍🦽🤓🤓💯👍

great product. I did an experiment with my Preppys, I used only the o-ring with no lube on the threads. It's working great
1 no leaks from 3 different pens

I haven't used the o-rings, but will when I change to eye dropper filling.

Thank I can make an eye dropper out of my platinum preppy

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.

I used these to seal my Platinum Prefounte along with some Goulet silicone grease, so I could eye dropper-fill it. 100% leak-free!

Want to enable my Preppy as an eyedropper fill.

Stopped the leak.

simple, but works perfectly.

They work great.

I followed the YouTube videos to convert my Platinum Preppy into an eyedropper pen. Slathering the silicone grease on the threads along with the O-Rings sealed everything up. Just check on leaks every few days/weeks to re-apply the grease.

Finally replaced my home-depot found ugly o-rings.

It is nice to be able to purchase these o-rings knowing they will fit and work properly. I have used the silicone grease on the threads but like the added protection the o-ring gives.

These have worked well for the two eyedropper conversions that I've done. Just be careful not to over tighten the threads on when converting a preppy (the threads can crack).

I was able to fill my clear Platinum Preppy and watch the ink slosh around inside. I used both an o-ring and some silicone grease. I also ended up using one of these o-rings on my Pilot Prera, which worked out well!

The o-rings fit great, after you stretch them a bit to get them on and make sure they are not twisted, the fit is great. Tips-#1use just a tiny little bit of the silicon lube on the o-ring to help it slide on better. #2 DON'T over tighten the pen barrel. If you do, it might look fine for a day or four but then it might start to leak all over your desk due to the small stress cracks around the threads. But if it happens just put the cartridge or converter in and it will still work fine.

Great stuff -- I prefer eye-droppers -- for my occasional long writing sessions. I therefore need these. The O-rings from Goulet pens are of good quality, and size for most of my pens that can be eye-droppered.

Worked as expected

I've just bought my first Platinum Preppy and these rings and the grease. The ring slides right on, perfect the first time. When I buy my 5th Preppy, I'll be buying another pack of these!

The pen arrived extremely quickly, and was well packaged, along with a lollipop and handwritten note.

I bought these items specifically to eyedropper. But aside from the ease of doing this, the quality of the nib is amazing for such an inexpensive pen. Anyone who wants to get into eyedroppering can't do better than this.

As expected for to get the seal.

Made converting my Plat Prep super easy.

Preppys are the first pen I've eyedropper converted. These rings, some Goulet silicon grease, a bit of attention to make sure the ring is properly placed and compressing when you close the pen, and you've got an eyedropper pen! I use dedicated Preppy EFs with Baystate Blue, so having a good seal is very important to me, and these are great.

These O-rings do exactly what they are supposed to do: seal the ink reservoir. Highly recommended.

I wanted to get a few Preppies to use for trying out ink samples with different nib sizes, so I had to get the O-rings and the silicone grease to convert the pens to eyedropper. Works like a charm, and the only clean up needed was getting some grease off my fingers. Great cheap way to get someone into fountain pens or to have something lying around for experimenting with inks.

OMG these are the best Prongs ever!

These are some great o-rings. They are in a round, o shape, and they are rings, so they are accurately labeled. They are stretchy, and if you stretch one of them to fit around the base of the barrel of your Platinum Preppy, just where the threaded part ends, it acts like a tiny rubber gasket, helping to seal your pen from leakage after you convert it. You will need some Silicone Goo and perhaps an Ink Syringe, also available at Goulet Pens, and of course you will need some ink, and they have plenty of that. If you are having difficulty converting your Platinum Preppy, I recommend inviting it out for a cup of coffee. Speak quietly but firmly about your convictions. Let it know that you care deeply about it. Invite it to pray with you. On a more serious note, these rings are just the right size, they do not break, and they are conveniently packaged in packets of four rings so that you do not have to get into your car and drive to the hardware store, where they will complain about the small size of your order, or worse yet to the big-box hardware place, where they will make you stand in line, and when you finally get to talk to a person, they will look at you like you've lost your mind. Just get what you need from Goulet, and you're all set.

The O-rings work well in my Platinum Preppy pens I converted for use as markers. Four weeks of use and no leaks. I don't know how they will perform when it comes time to reopen and refill my eye-droppered (it that a word?) Preppy, but the low total cost of the pens, o-rings, and grease makes it worth a try.

The O-rings were an excellent choice when I decided to convert my Platinum Preppy pens to eyedropper fill. They are simple to install and working in conjunction with Goulet silicon grease, they form a solid seal with no leakage at all. I can recommend them without reservation. Brian and his team are a pleasure to do business with.