Genuine OEM HP DeskJet 1000Cse Ink and Supplies
The 1000Cse uses HP 45 black and HP 41 tri-color ink. An HP 45 twin pack contains two black cartridges, so it gives you a spare black cartridge rather than covering both ink types.
Toner Buzz carries genuine HP 45 singles and twin packs, along with individual HP 41 cartridges. Choose a single when you need one cartridge, or the black twin pack to keep another on hand; color ink is a separate HP 41 purchase.