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

This design enables A+2000 custom air filters to maintain performance over the years

The A+2000 line is easy to maintain with no need to buy oils or adhesives to enhance effectiveness

Instead of face loading (particles captured on the outer surface of the filter)

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

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.