Pad Refills (Pack of 6 Pads) - 21" x 23 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

The "Practical Pleat" contains over 500% greater surface area than a MERV 10 one-inch pleat

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

You may know them as washable air or even permanent air filters

Pad Refills (Pack of 6 Pads) - 21" x 23 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.