The GreenEngineered HP LaserJet CB540A Black Toner Print Cartridge is a remanufactured toner cartridge compatible with HP LaserJet CP1518ni, HP LaserJet CP1515n, and HP LaserJet CM1312 printers. It uses laser print technology and is designed to be eco-friendly. The unit is sold as a single black toner cartridge for HP printers.