The Office Depot Black Ink Cartridge for HP 21 OD221 is a remanufactured ink cartridge designed for use with HP printers. It is compatible with various models such as DeskJet, Fax, and OfficeJet, providing high-quality black printing results. This sealed box contains one unit of ink cartridge, making it convenient for users to replace their existing ink supply and ensure continuous printing performance. With its reliable brand name and compatible models, this black ink cartridge is a dependable choice for anyone in need of printer ink.