I ordered this to put into my Tech Pure air filter system. Even though this filter said it was a 20x20x4 filter it would not fit inside my air cleaner. The pleated filter was very irregular and the cardboard that was used to hold the pleats was flimsy and the pleats were not uniform.
These are terrific filters. Much easier to slide in and out of the filter housing than dealing with my old electronic filter that required frequent cleaning. These fit into older honeywell electronic filters. Quick delivery.
Overall this was a well made filter, very study and well constructed. Five stars for product quality. However, the thickness is 4.25" NOT 4" as advertised. I received it so I could replace two 2 inch filters that had previously been put into the system, but it was simply too thick to get into the opening. If your opening is at least 4.25", this is a great choice for you - just measure first!
This is what fits my furnace, and I trust this filter/brand better than no-brand filters. i.e. I'm not trying to save money on this, as I'd rather have more dust, pollen and whatnot caught in the filter. I think there's a mention that the filter can last 1 year, but your mileage will vary. In my case, I change it 3 times per year, and each time it's dirty. A dirty filter might catch less "Stuff", but mostly it will be less efficient in letting the air go through. That means wasting on heat (and/or cooling). So I prefer changing as often as with the thinner filters.
pros: works. Just remove it and look at it... cons: expensive. Also no option to get recurring buys.