These printers use the 51640 cartridge:

HP CopyJet

HP CopyJet M

HP DesignJet 230

HP DesignJet 230 D-Size

HP DesignJet 230 E-Size

HP DesignJet 250

HP DesignJet 250 C

HP DesignJet 250 C D-Size

HP DesignJet 250 C E-Size

HP DesignJet 330

HP DesignJet 330 D-Size

HP DesignJet 330 E-Size

HP DesignJet 350 C

HP DesignJet 350 C D-Size

HP DesignJet 350 C E-Size

HP DesignJet 430

HP DesignJet 450 C

HP DesignJet 455 C

HP DesignJet 455 CA

HP DesignJet 488 C

HP DesignJet 488 CA (24inch)

HP DesignJet 488 CA (36inch)

HP DesignJet 488 CA Wide Format

HP DesignJet 650

HP DesignJet 650 C

HP DesignJet 650 C PS

HP DesignJet 650 CD

HP DesignJet 650 CE

HP DeskJet 1200 C-PS

Encad CadJet

Encad Cadet II

Encad Cadjet II (36 inch)

Encad Cadjet III

Newgen Vista Color Plotter

Riso-Corporation RJ 1100