Compatible with: Lexmark MS Series: MS321dn, MS421dn, MS521dn, MS621dn, MS622de This is the Compatible Higher Yield Version of Lexmark 56F1000 black compatible toner cartridge Page Yield*: 15,000 For best results, store in a cool, dry place. Use within 3 years of purchase for optimal performance.*at 5% coverage (ISO/IEC standard) All LD compatible and remanufactured cartridges are quality tested to ensure long-lasting use and bold, vivid print on every page Please contact us first with any product issues. We want all of our customers to be happy because happiness matters.