TWSBI Diamond 50 Ink bottle: designed for every type of fountain pen and specific upper cap design for Diamond 530, 540, 580, Diamond Mini, and Classic fountain pens.

The TWSBI Diamond 50 ink bottle is a 50mL glass bottle with anodized aluminum top that is the perfect accessory for any fountain pen addict! The bottle allows for easy refilling of your fountain pen by offering an upper reservoir that fills with ink when you turn the bottle upside down (cap on of course!) The reservoir provides a set amount of ink to fill your pen and avoids the hassle of dipping your pen to the bottom of the bottle, trying to get each drop out as the bottle runs low.

As an added benefit to those who own the Diamond 530, 540, 580, Diamond Mini, and Classic fountain pens you can use the colored band attachment to refill your TWSBI fountain pen without having to dip the nib in the ink at all! Simply unscrew the grip section of your Diamond or Classic fountain pen and attach it to the filling apparatus. Turning the piston knob of the fountain pen will draw the ink up into your pen. No more inky fingers!!