These printers use the P2V79A cartridge:
Click On a Printer to View it's Cartridges
          HP DesignJet Z-6 DR PS VTR 44 IN.
          HP DesignJet Z-6 PS 24 IN.
          HP DesignJet Z-6 PS 44 IN.
          HP DesignJet Z-9 + PS
          HP DesignJet Z-9 DR PS VTR 44 IN.
          HP DesignJet Z-9 PS 24 IN.
          HP DesignJet Z-9 PS 44 IN.
          HP DesignJet HD PRO 2