Pad Refills (Pack of 6 Pads) - 21" x 23" x 1" Quantity:Default the A+2000 uses no foam

the A+2000 uses no foam that may clog

Filtering inserts are anti-microbial and are more efficient in capturing particles

To find the size the old unit should have sizing information printed on it

One way to overcome this problem is to increase the surface area of the filter media

Pad Refills (Pack of 6 Pads) - 21" x 23" x 1" Quantity:Default the A+2000 uses no foamPACK 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.