These printers use the C4911A cartridge:
Click On a Printer to View it's Cartridges

          HP DesignJet 500
          HP DesignJet 500-24 IN
          HP DesignJet 500-24-Inch
          HP DesignJet 500-42 IN
          HP DesignJet 500-42-Inch
          HP DesignJet 500 PS
          HP DesignJet 500 PS 24 IN
          HP DesignJet 500 PS 24-Inch
          HP DesignJet 500 PS 42 IN
          HP DesignJet 500 PS 42-Inch
          HP DesignJet 510
          HP DesignJet 510-24 IN. Wide Format
          HP DesignJet 510-42 IN. Wide Format
          HP DesignJet 800
          HP DesignJet 800-24-Inch
          HP DesignJet 800-42-Inch
          HP DesignJet 800 PS
          HP DesignJet 800 PS 24-Inch
          HP DesignJet 800 PS 42-Inch
          HP DesignJet 815 MFP
          HP DesignJet 820 MFP Wide Format
          HP DesignJet 820 MFP
          HP DesignJet 820 PS