Pad Refills (Pack of 6 Pads) - 20 3/4" x 22 1/4" x 1" Quantity:Default The permanent frame is constructed

The permanent frame is constructed of space-age plastics that are resistant to corrosion

The Pad and Frame Air Filter involves a permanent frame and replaceable filtration pad inserts

A higher MERV rating means that the air filter that you are about to purchase possesses a higher amount impurity filtration ability than your ordinary filter

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

Either way

Pad Refills (Pack of 6 Pads) - 20 3/4" x 22 1/4" x 1" Quantity:Default The permanent frame is constructedPACK 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.