the physical dimensions are > 4", actually close to about 4.5". Be sure you're housing will accommodate 4.5" before purchasing. Can't comment on the function because these would not fit.

I've been using these products for over 10 years. I will search out stores that carry them and have been pleased with the increased efficiency levels the company keeps producing.

These filters are difficult to fine in stores because of their size. The cost is way more than other size filters, and I fail to see why because they are basically paper and a wire mesh construction.

I purchase one of your other filters and seen that it did not preform as well, when I purchase the Healthy living filter, I saw a big difference, my wife were able to sleep better at night and there was less dust on top of my frig,

Remember these filters are for Standard size Returns. However there are HVAC companies that deliberately use Grille size Returns to make a customer buy their filters. GRILLE SIZE Returns are slightly smaller than the Standard counterparts.

I use this filter in my home with three cats and a dog. Filtrete helps keep the dust and dander to a minimum. I can't wait to try the Odor Reduction filter, too.

According to our service technician, pet hair can wreck havoc on your HVAC system. The Healthy Living Air Filter addresses the issue so that it is no longer a problem. Works great!

We have used Filtrete for years and it works fantastic. Because it works so well, we find ourselves changing the filter more often than the package says. It is amazing how much it collects and keeps out of our air.

As a long time Filtrete user, I remain impressed at its ability to do exactly what it's supposed to do. I have less dust, less odor, and just generally cleaner smelling air. It is worth the price.

I've always used Filtrete since I bought my house 15 years ago but lately my spouse developed adult onset asthma and moving from the 800 to the 1200 product has made a huge difference in our air quality. Great for households with pets.