These printers use the P2V81A cartridge:

HP DesignJet Z-6 DR PS VTR 44 IN.

HP DesignJet Z-6 PS 24 IN.

HP DesignJet Z-6 PS 44 IN.

HP DesignJet Z-9 + PS

HP DesignJet Z-9 DR PS VTR 44 IN.

HP DesignJet Z-9 PS 24 IN.

HP DesignJet Z-9 PS 44 IN.

HP DesignJet HD PRO 2