Lexmark 56F1X00 56F0XA0 Toner Cartridge Black MS421 MS421dn MS421dw MS521 MS521dn MS621 MS621dn MS622de - Sun Data Supply
PrinterDash Compatible Replacement for Lexmark MS-321/MS-421/MS-521/MS-621/MS-622/MX-321/MX-421/MX-521/MX-522/MX-622 Series Drum/Toner Value Combo Pack (1-Drum/4-Toners) (56F0ZA0_1PK/56F1H00_4PKVB) - Walmart.com
Lexmark MX421ade Black Toner Cartridge, Genuine (G4139)
Amazon.com: Be Green Ink Compatible Replacement Toner Cartridge for Lexmark MS321 MX321 MS421 MX421 MS521 MX521 MS621 MX621 MS321dn, MS421dn, MS421dw, MS521dn, MS621dn, MS622de, MX521de - 56F1H00 15K Black Toner : Office