blue 411 filter

Listings describe the particle media as polypropylene or polyester, with an odor-adsorbing layer made of activated carbon/charcoal.

They typically include an activated carbon/charcoal layer or mesh that adsorbs and deodorizes household smells, helping to trap light odors, smoke, and some VOCs.

Listings show HEPA-style particle filters, activated carbon/charcoal filters, and combo replacements that combine particle media with an activated-carbon layer in a single filter.

Listings offer single filters and multi‑packs—commonly 1, 2, 3, or 4 per package. One product detail unusually lists 'Package Quantity: 120,' so verify the product page for the advertised pack size.

Most listings recommend replacing filters about every six months; one listing specifies this interval for continuous 24/7 use.

Many HEPA-style listings state 99.97% particle capture, commonly specified at 0.3 microns; a few listings claim performance down to 0.1 microns for certain filters.