The original Canon CLI-521BK photo black cartridges are popular cartridges in a wide range of Canon printers, including the Pixma MP550.  The Canon CLI-521BK black cartridge contains 9ml of ink and is designed to be used specifically for photo printing. The CLI521BK cartridge is ideal for those looking to get the most out of their photo printing and like all Canon printers, the CLI521BK cartridge will produce excellent quality results when printing. The CLI-521BK includes Canon`s ChromaLife 100 ink, a dye based ink designed to work perfectly with photo papers for improved quality. The ChromaLife 100 ink in the CLI521BK cartridge has been designed to give longevity by being fade resistant, light resistant, gas resistant and works against heat and humidity over a sustained period of time. The CLI-521BK cartridge is therefore great value for money for any of the many Canon printers it is compatible with, all listed above. Our original Canon CLI-521BK photo black cartridges for this range of Canon printers is amongst the lowest priced on the Internet. All our prices include VAT and delivery so the price you see is the price you pay.