These printers use the 3ED68A cartridge:
Click On a Printer to View it's Cartridges
          HP DesignJet T-210-24-IN
          HP DesignJet T-230
          HP DesignJet T-230-24IN
          HP DesignJet T-250
          HP DesignJet T-250-24IN
          HP DesignJet T-630
          HP DesignJet T-630-24IN
          HP DesignJet T-630-36IN
          HP DesignJet T-650
          HP DesignJet T-650-24IN
          HP DesignJet T-650-36IN
          HP DesignJet Studio 24 IN
          HP DesignJet Studio 36 IN
          HP DesignJet Studio Steel