DO NOT BUY CHEAP FIBERGLASS FILTERS!!! The Federal Gov't should ban them!! All those gaps and spaces you can see through the fiberglass filters......that is the path that the dust will take right to your blower,heat exchangers, A/C a-coil, then the ducts. Buy the cheap grade of Natural Aire at Walmart or Home Depot and replace often. A 3 pack is on sale often for 5 or 6 bucks, thats $2 each. Even if you replace every 2 weeks think of the money youll save on wear and tear and service calls, equipment efficiency. BY the way they should ban those 3M $15-$30 filters.....way too restrictive. Pleats are spaced way too close together...nothing like tripping limits!!