Lexmark 56F0Z00 Black return program imaging unit Compatible with MS321dn, MS421dn, MS421dw, MS521dn, MS621dn, MS622de, MX321adn, MX321adw, MX421ade, MX521de, MX521ade, MX522adhe, MX622ade, MX622adhe laser printer Yield of up to 60000 pages. Print Technology - Monochrome Laser