TWSBI Diamond 580ALR Navy Blue Fountain PenA deep navy colour for a controlled feel The TWSBI Diamond 580ALR Navy Blue takes the proven 580 model and adds a darker, more restrained tone, with a machined aluminium grip. It keeps the full demonstrator experience, but moves the feel in the hand to more control and texture, for a more serious presence. A pen for professional notes. What sets it apart Piston filling system, with high ink capacity Navy blue serious tone, suited to professional