These printers use the 56F1000 cartridge:
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