These printers use the C4912A cartridge:

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