TWSBI Diamond 580 Fountain Pen – IRIS The TWSBI Diamond 580 is a piston filling pen. This means that you don’t need a converter to use bottled ink with this pen. Instead, dipping the nib into a bottle of ink and turning the piston knob will suck ink directly into the body. This gives the pen an enormous ink capacity, and makes refilling the pen quite an enjoyable activity. The body of this pen is faceted in an aesthetically pleasing diamond pattern. This is where the “Diamond” in the name comes from. Apart from being a beautiful design, the clear body also makes it very to tell how much ink is left at a glance. Additionally, it’s great for showing off brightly coloured inks. The Diamond 580 also features metal accents on the cap, grip section, and around the piston knob. The steel nib is smooth and quite wet, and matches these accents well. These details make for a pen that looks great and performs just as well. Additionally, if you’re a fan of this pen, you will love the TWSBI Diamond 50 ink bottle. After removing the nib, the Diamond 580 fountain pen can be attached directly to this bottle. This makes it very easy to achieve a complete fill.
