This is not something that I can review. I did my research on what I needed, since I have serious lung problems, I am in a senior facility, I have a dust problem, and I am 84. I assume they are what they say they are, they arrived quickly, I installed them with the help of my maintenance man who put a piece of foam weatherstripping on top and one side to make them fit very tight so nothing can get around them, and I hope they work as advertised. I only wrote this because they pushed every day to get me to say something. Otherwise I would not have written about something I am not qualified to evaluate.
I have been purchasing air filters for years from this company. They always arrive on time they are well packaged. Just a basic dependable company with a great product.
Very helpful over the phone. But I havent gotten the filter yet, so when I place an order on Thursday and get a frigging request for a starred review in 48 hours, I wonder.