These printers use the MLTD203U cartridge:
Click On a Printer to View it's Cartridges
          Samsung ProXpress M-4020 ND
          Samsung ProXpress M-4024 ND
          Samsung ProXpress M-4070 FX
          Samsung ProXpress M-4070 FR
          Samsung SL M-4020 ND
          Samsung SL M-4070 FR