These printers use the 3ED68A cartridge:

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