The TWSBI Diamond 580RBT fountain pen has a transparent barrel so you can see the inner workings of the pen as well as the ink colour. The TWSBI Diamond 580RBT features stunning red and blue coloured barrel. The pen has a benchmark ink-filling mechanism and has all detachable parts. TWSBI Diamond 580RBT allows the user to disassemble and reassemble the pen and fully experience the characteristic aspects of owning and using a fountain pen. The TWSBI Diamond 580RBT fountain pen comes with a broad nib and is a great addition to you fountain pen collection.