Pad Refills (Pack of 6 Pads) - 19 7/8" x 21 1/2" x 1" Quantity:Default these can be purchased in

these can be purchased in any conceivable size

than standard fiberglass filters purchased at retail outlets

oxidation and deterioration

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

such as dust

Pad Refills (Pack of 6 Pads) - 19 7/8" x 21 1/2" x 1" Quantity:Default these can be purchased inPACK 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.