Comments about Airpura Replacement Pre-Filter (2 PACK):
These filter are great. They don't have to be replaced often and you can vacuum 'em from the outside of the unit saving time and energy since you don't have to remove them. The price also is right. I understand that one filter can last up to 12 months, then they need to be replaced. So far I've been using the unit for over a month and I haven't seen any difference in performance. That's a good sign that it's doing what it's supposed to do.