The vacuum cleaner requires a Hepa bag and this pack of four comes with a spare filter. Two dogs and a cat are really testing a cheap vacuum cleaner, so we bought a Johnny Vax XV10. The bag works great and one filter for every 4 bags means the cleaner lasts longer. We used a different vacuum for a week and everyone sneezed until the new Johnny Vac came back and picked up all the fur and dander.