These printers use the Q3961A cartridge:
Click On a Printer to View it's Cartridges
          HP Color LaserJet 1500
          HP Color LaserJet 1500 L
          HP Color LaserJet 1500 LXI
          HP Color LaserJet 2500
          HP Color LaserJet 2500 LSE
          HP Color LaserJet 2500 L
          HP Color LaserJet 2500 N
          HP Color LaserJet 2500 TN
          HP Color LaserJet 2550
          HP Color LaserJet 2550 L
          HP Color LaserJet 2550 LN
          HP Color LaserJet 2550 N
          HP Color LaserJet 2800
          HP Color LaserJet 2820
          HP Color LaserJet 2820 All In One
          HP Color LaserJet 2830
          HP Color LaserJet 2840
          HP Color LaserJet 2840 All In One
          HP LaserJet 1500
          HP LaserJet 1500 Series
          HP LaserJet 2500
          HP LaserJet 2500 Series