Genuine OEM HP DeskJet 850 C Ink and Supplies
The 850C's HP 45 black twin pack is useful for keeping a spare black cartridge. It contains two of the same cartridge, while the printer's color ink comes in a separate HP 41 tri-color cartridge.
Toner Buzz carries genuine HP 45 black ink individually and in twin packs, along with individual HP 41 tri-color ink. Choose the ink type you need; buying the black twin pack doesn't cover a color-ink purchase.