Medium 2-tone Edison Nib
I purchased an extra medium 2-tone nib for an older Edison Hudson pen. In short, I love it.
It was easy to swap out the nib and it is a very smooth writer. While an excellent pen to start with this new nib really improves the experience for me and will mean that this pen will get much more use and attention.
I considered swapping just the nib itself on an Edison Collier (it had too fine a nib for me), but then I saw that AP sold the whole nib/feed unit from Edison. If the Edison logo is important to you, pay the extra $10 and get this product. You can simply screw this into the section. Less risky than yanking and reinstalling just the nib.