These printers use the 56F1000 cartridge:
Click On a Printer to View it's Cartridges
          Lexmark MS 321
          Lexmark MS 321 DN
          Lexmark MS 421
          Lexmark MS 421 DW
          Lexmark MS 421 DN
          Lexmark MS 521
          Lexmark MS 521 DN
          Lexmark MS 621
          Lexmark MS 621 DN
          Lexmark MS 622
          Lexmark MS 622 DE
          Lexmark MX 321 ADW
          Lexmark MX 321 AND
          Lexmark MX 421 AND