These printers use the C6625 cartridge:
Click On a Printer to View it's Cartridges
          HP DeskJet 816 C
          HP DeskJet 825 C
          HP DeskJet 825 CVR
          HP DeskJet 840 C
          HP DeskJet 841 C
          HP DeskJet 842 C
          HP DeskJet 843 C
          HP DeskJet 843 CXE
          HP DeskJet 845 C
          HP DeskJet 845 CVR