Aside from Fountain Pens, the most universally loved rollerball pen/cartridge is the Pilot G2. Am I wrong about this??? It's the smoothest ink and the go-to pen of all time. Hands down, the G2 is the bomb of a pen, right? Why then, do not most custom pen manufacturers make pens which take the G2? ??? It's almost like the consciously avoid the G2. Recently I bought a Ti2 Techliner. It takes a Uni 207 (or so I thought). No, now the new ones only take a Uni Jetstream (which is not a gel pen). For the coolest pen, why not take a G2???? I just don't get it. You can't hardly find a custom pen which will accept the all-time-favorite, Pilot G2 refill!! They just don't do it, and I don't get it.