70ml bottle of high-quality TWSBI fountain pen ink, available in 5 different colors: Black, Blue-Black, Sapphire Blue, Midnight Blue, and Red. Frosted glass ink bottle ships with a special nozzle that allows the last bit of ink in the bottle to be used, and is also compatible with the cap of the Diamond 580 ink bottle, allowing you to fill your TWSBI 580 completely and mess-free.

With the exception of Blue-Black, TWSBI inks are not waterproof.