Pad Refills (Pack of 6 Pads) - 20" x 21 1/4" x 1" Quantity:Default And there are no metal

And there are no metal parts that could lead to corrosion or oxidation within the filter

oxidation and deterioration

One way to overcome this problem is to increase the surface area of the filter media

They are easy to install with custom air filters made to the sizes that you specify

Filtering inserts are shipped in an easily stored packet

Pad Refills (Pack of 6 Pads) - 20" x 21 1/4" x 1" Quantity:Default And there are no metalPACK of 6 pads for Pad and Frame Air Filters Filtering inserts are anti microbial and are more efficient in capturing particles, such as dust, ragweed, pollen, etc., from the air stream, than standard fiberglass filters purchased at retail outlets. Filtering inserts are shipped in an easily stored packet.