TWSBI Diamond 50 Ink Bottle

TWSBI Diamond 50 Fountain Pen Ink Bottle – 50ml Glass Bottle with Filling Reservoir

Crafted with both style and practicality in mind, the TWSBI Diamond 50 Ink Bottle is a must-have for fountain pen enthusiasts. This 50ml glass bottle features a premium anodized aluminium cap and an innovative dual-chamber design that simplifies the refilling process.

Unlike standard ink bottles, the Diamond 50 includes a clever upper reservoir that fills with ink when the sealed bottle is inverted. This makes drawing ink far easier—especially when the bottle is running low—by eliminating the need to submerge your nib deep into the bottle.

Designed with versatility in mind, this bottle is compatible with all fountain pens, but it's especially useful for TWSBI Diamond series pens (models 530, 540, 580, and Mini). For these, an included filling adapter allows you to refill directly through the barrel—no nib dipping required. Simply detach the front section of your pen, connect it to the reservoir, and turn the piston knob to fill. Clean, efficient, and inky-finger-free.

Available cap colours: Blue, Black, Silver, and Red.
Note: Ink not included.