This Genuine/Original HP 51A (Q7551A) Toner Cartridge in Black is compatible with HP printers. This cartridge ensures that your printing quality is top-notch and lasts longer with excellent yields. The HP 51A is a reliable toner cartridge that ensures a clear and crisp print every time. Its compatibility with HP printers means it is an excellent choice for those who want to print high-quality documents for business or personal use. The unit quantity is one, and the color is black.