A threaded piston converter for most fountain pens.
Monteverde pens are a company focused on innovation, compatibility and unique style. Their range consists of luxury pens, state of the art modern designs and a huge amount of different pen refills to fit most pens on the market today. Here at The Online Pen Company we focus on the refills, and making it easy to shop, and understand the huge range.
In essence, each refill has a product code, which explains what the compatibility, design and colour is. Here is a quick guide on Monteverde refills coding sytem, that should make it easy to understand.