Designed specifically to fit all 16" x 25" F50E, F50A. The F50A, F50E have a prefilter slot and a post-filter slot. One Permatron carbon filter slides in to the post-filter slot. The carbon filters are the full size of the air cleaner and not split in pairs like the original Honeywell prefilters.
Permatron charcoal filters exceed manufacturer specs with 14 grams of carbon per square foot along with a low 0.06 wg air resistance.
Vapors are pulled by molecular action in to tiny pores and held. In manufacturing the carbon, the activation process creates millions of micropores. The pores are sized and formulated to remove common household VOC's.
Permatron filters are made in Illinois. The foam, activated carbon, poly-propylene, aluminum mesh and steel frame are all products of the USA.
The genuine Honeywell prefilters are stamped with Product of Mexico.