Twsbi Eco Cosmos Onyx Fountain Pen - 3 nib optionsA great fountain pen with an onyx colored nib and it's made for beginners! It features a swirling blue green patterned cap and piston knob, accented with an onyx colored nib and trim. It's ideal for everyday writing. This is a piston filler fountain pen. There's no need for cartridges or a converter. Simply unscrew the end cap, dip into ink, screw back the end cap and you're ready to write! The pen has an inner cap to insure a perfect seal when