Great way to retrofit 1" filter return registers with better filters
These have worked great so far.  I don't have any way to verify that the filter performance is as stated, but I really like the fact that I can retrofit these in many of my existing filter registers (which only support 1&#34; thick filters).  If they last the claimed 6 months compared to 1 month for a standard 1&#34; filter, they're a great value.<br /><br />The only thing that gives me pause is the fact that multiple MERV (filter efficiency) ratings are printed on the cardboard exterior, and one has a hand-made checkmark next to it to indicate the filter rating.  It may be that they use different types of filter media in a common cardboard frame, but it somewhat feels like they sell the same filter and just mark whatever rating someone paid for.
Rating: 4 stars