Review on Nispira Foam Filter Set - Compatible with Shark NV42 Deluxe Upright Vacuum Cleaner. Alternative to Part #XFF36. Suitable for UV402 UV410, NV36, NV36A, NV42, NV44, NV46, NV46C. 2 Sets. by Stan Myers

These aren't "exactly the same" as the branded units or the ones that came with my vacuum, but they are a worthy replacement. I used my originals for 2 years, just washed them from time to time and let them dry completely. They don't seem strong enough for this, but I think I can wash and use them a few times before replacing them. Luckily, they are not expensive for those who prefer not to wash and reuse them.