The Lexmark 56F1X00 Extra High Yield Black Cartridge is a genuine product manufactured by Lexmark specifically for the Lexmark MS521 model printer. This high yield toner cartridge, designed for laser print technology, offers a long-lasting and efficient printing experience. Made in China, this unit is compatible with Lexmark printers and provides excellent black printing results for your documents and images. With a unit quantity of 1, this black cartridge ensures a high-quality and consistent printing output every time.