The HP Invent 57 TRI Color Ink Cartridge is a single unit that offers cyan, yellow, and magenta colors for inkjet and thermal print technology. Specifically designed for HP printers, this cartridge is compatible with models like the HP 57 and C6657AN. While it may be expired, it can still be used for printing purposes within the specified expiration date. With its reliable brand reputation and wide compatibility, this ink cartridge provides quality and convenience for your printing needs.