Pad Refills (Pack of 6 Pads) - 21 1/2" x 23 1/2" x 1" Quantity:Default and the greater the pressure

and the greater the pressure drop it creates

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

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

Pad Refills (Pack of 6 Pads) - 21 1/2" x 23 1/2" x 1" Quantity:Default and the greater the pressurePACK 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.