Canon's exclusive Think Tank ink management system, a feature on the i9100 Photo Printer and other compatible printers, is designed to help eliminate ink waste and reduce printing costs. It allows you to replace only the color that runs out, rather than the entire cartridge. A unique low-ink sensor alerts you when ink levels are low, so you can drop in a new tank.Ink cartridge compatible with the following printers: BJC-8200, i860 Series, i900D, i9100, i950 Series, i960 Series, i9900, PIXMA iP4000, S800, S820, S820D, S830D, S900 and S9000.