TWSBI Diamond Ink Bottle

TWSBI's glass Diamond Ink Bottle is a beautiful ink well that can be used with any fountain pen. However, TWSBI's Classic, Diamond, Diamond Mini, and Precision pens fit for a unique filling system. The top portion of the cap can be removed to reveal a specialized filling port to suck up the ink! OR, unscrew the entire cap for regular use. Nifty, huh? 

If that wasn't enough, it also includes a plastic reservoir that assists getting the last of the ink in your bottle. Genius.