Pad Refills (Pack of 6 Pads) - 17 1/2" x 19 1/2" x 3/4" Quantity:Default and the greater the pressure

and the greater the pressure drop it creates

Any Kind of Filter's Extended Surface Pleated Filters outperform ordinary furnace filters with medium efficiency and are designed for lower pressure drop

Includes one Frame and PACK of 6 pads

if not you can measure it or check the HVAC unit and the owner‰۪s manual

oxidation and deterioration

Pad Refills (Pack of 6 Pads) - 17 1/2" x 19 1/2" x 3/4" 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.