The TWSBI Diamond 580 Fountain Pen has an innovative design with a transparent barrel so you can see the inner workings of the pen as well as the ink colour. The Diamond 580 features a benchmark ink-filling mechanism and has all detachable parts. TWSBI Diamond 580 allows the user to disassemble and reassemble the pen and fully experience the characteristic aspects of owning and using a fountain pen. Comes with broad nib