These printers use the 841850 cartridge:
Click On a Printer to View it's Cartridges
          Ricoh MP C-3004 EX
          Ricoh MP C-3504 EX
          Ricoh MP C-4503
          Ricoh MP C-4504
          Ricoh MP C-4504 EX
          Ricoh MP C-5503
          Ricoh MP C-5504 EXSP
          Ricoh MP C-5504 SP
          Ricoh MP C-6003
          Ricoh MP C-6004
          Ricoh MP C-6004 EX