Pick the brand
The brand is printed on the same plate as the model number.
Filters that come up most
The part numbers listed for the most air purifiers in the index. Open one to see every model it fits.

965432-01HEPA filter28 air purifiers
HE1FKBASHEPA filter22 air purifiers
HRF-C2HEPA filter19 air purifiers
HRF-B1Pre-filter18 air purifiers
HRF-B2Pre-filter18 air purifiers
HE2FKBASHEPA filter18 air purifiers
24000HEPA filter13 air purifiers
HE1FKPETHEPA filter12 air purifiers
974527-01HEPA filter11 air purifiers
115115HEPA filter10 air purifiers
1712-0004-10HEPA filter10 air purifiers
1712-0004-11HEPA filter10 air purifiersWhere the model number is
On air purifiers, the plate or sticker sits in one of a few places.
Air purifiers: On a label on the bottom or the back of the purifier.