Pardon me for asking, but what does ED mean? Everyday Carry? I am also looking for a converter that will work with my 1980s No Nonsense pen. Thank you for any help you can give me.
ED stands for "eye-dropper". In some of the earliest days of fountain pens (a century ago), before there were sophisticated filling systems, pens were made where the entire barrel was meant to hold the ink. In the simplest version the nib and section would unscrew and you would fill the barrel with ink using - you guessed it - an eye-dropper. The term stuck at some point.
These days there are still pens being made for this (often inexpensive ebonite pens) and many people will take any inert-bodied pen (plastic, ebonite, anything that doesn't have metaillic parts) and "ED" them. Why? Well, it's basically going to give you the maximum amount of ink. Why wouldn't you do it? Well, it can be messy, rarely do people use that much ink, and you have a problem of "burping", which is what occurs when part of the ink is used up - the air in the barrel heats up from the warmth of your hand, expands, and ink can 'burp' out onto the page in drops.
Frankly, I have no use for that large a body of ink, though I have one or two vintage (very old) pens that are ED by design that I occasionally ink up; the reason for this is that they happen to also have fabulous nibs.