From Amazon
Canon PGI-550 original Tintenpatrone Schwarz für Pixma Inkjet Drucker MX725-MX925-MG5450-MG5550-MG5650-MG6350-MG6450-MG6650-MG7150-MG7550-iP7250-iP8750-iX6850
Click and Keyboard
Canon Pixma PGI-550PGBK Ink Cartridge Photo Black 6496B001
Global Ape
Canon PGI-550 Black Ink Cartridge - 6496B001