The Pilot Parallel Pen Ink Cartridges are specially formulated for calligraphy use in the Parallel Pens and should not be used in any other Pilot cartridge fountain pen.Each box contains 6. Available colors include: Black, Navy, Red, Green, Purple, Pink, Turquoise and Assorted. The assorted pack includes Orange, Sepia, Light Green, Blue and Yellow in addition to the colors sold individually.