TWSBI Ink Bottle Diamond 50 aluminum polished

The TWSBI Diamond 50 ink bottle is a 50-ml glass bottle with a polished aluminium cap – designed as a refilling station for TWSBI fountain pens in the Diamond series. Inside, a small plastic reservoir works by inverting the bottle to dispense a defined amount of ink, enabling clean, controlled filling. Owners of a Diamond 530, 540, 580 or Mini benefit from the included screw-on adapter, which allows refilling without the nib ever touching the ink.

Features

• Integrated ink bottle reservoir: A plastic insert inside fills with a set amount of ink when the bottle is inverted. Your pen dips only into this reservoir – no fishing at the bottom of the bottle, even when it's nearly empty.
• Screw-on adapter for Diamond fountain pens: The barrel of a Diamond 530, 540, 580 or Mini screws directly onto the adapter. Turning the piston knob draws ink without the nib making contact – your nib stays clean, and so do your fingers.
• Glass bottle with polished aluminium cap: The smooth, cool aluminium cap seals tightly and gives the bottle a sleek, reduced weight in hand. Clear glass makes the current fill level visible at all times.
• 50 ml capacity: Ample volume for daily use or storing a favourite ink – without frequent replenishing.
• Supplied without ink: The bottle is compatible with any standard water-based ink and remains colour-neutral – ideal for decanting your own ink supplies.

Use & Tips

• Filling via the reservoir: Unscrew the cap, invert the bottle with the cap attached, wait briefly – the reservoir fills. Right the bottle, dip your pen, done. Even the last drop of ink remains accessible.
• Direct filling with Diamond adapter: Unscrew the barrel of your Diamond fountain pen, attach it to the bottle neck, turn the piston knob. Filling takes seconds, and your nib never touches ink.
• As an ink depot: The tightly sealing glass bottle is perfect for decanting larger ink bottles into handy 50-ml units – practical when travelling or at your desk.
• Cleaning: Rinse the reservoir and adapter with clear, lukewarm water. Before using a new ink, a brief soak of the adapter is recommended if it's been stored dry for a while.

For TWSBI Enthusiasts

The screw-on adapter is precisely engineered to the TWSBI Diamond piston mechanism: the section ring of the fountain pen engages directly into the bottle neck, so no gap forms during filling and no ink escapes. The reservoir principle is borrowed from professional ink bottles used in calligraphy studios – here it's adapted to a compact everyday bottle format. If you use multiple inks, you can reserve the bottle as a labelled stock bottle for one ink and reliably prevent cross-contamination.

Technical Specifications