![Pilot Mixable Parallel Pen Color Cartridges 12pk](http://shop.littleislandcrafts.com/cdn/shop/products/77312_{width}x.jpg?v=1590866208)
From the manufacturer:
Add a Twist to Your Writing! A major breakthrough in calligraphy pen design, the unique parallel plate structure achieves a more beautiful and sharper handwriting than existing calligraphy pens. Mixable colors-simply touch the nibs of two Parallel Pens together to create beautiful color graduations.