TWSBI Diamond 50 Ink Bottle

This glass inkwell from TWSBI has a black anodized aluminum top with silver accents. It has an ink capacity of approximately 50ml.

You can use the specific upper cap design to cleanly and directly fill your TWSBI Diamond 580, Classic, Mini, or Precision fountain pen, or simply unscrew the upper cap to fill any fountain pen from the inkwell itself.