Lexmark 56F1U00, 56F0UA0 Ultra Hi-Yld Compatible Toner-Black. Compatible with 56F1U00, 56F0UA0 - Black. Fits Models: MS521dn, MS621dn, MS622de, MX521ade, MX521de, MX522adhe, MX622ade, MX622adhe - Ultra High Yield