Genuine OEM HP DeskJet 820 Cse Ink and Supplies
The 820Cse's HP 45 twin pack includes two identical black ink cartridges. It lets you keep a second black cartridge on hand, but doesn't include the HP 41 tri-color ink used for color printing.
Toner Buzz carries genuine HP 45 black singles and twin packs, and individual HP 41 tri-color cartridges. Choose the single HP 45 for one black cartridge, the twin for a spare, or HP 41 when you need color ink.