I purchased a 20x25x4 filter to replace my existing one. This MERV 8 filter is much less dense and more fragile than my previous MERV 10. I expected it to be less dense, but am not experienced enough to know if this is an atypical amount. This 20x25x4 filter is significantly smaller in all three dimiensions than my previous 20x25x4 filter, and I had to make a stand-off to ensure a good fit against the furnace intake. The measurements on the site are correct, I just did not realize that the "standard" sizes are so non-standard. use measurements instead.
Assuming the filters themselves do their job, the ordering proceedure, and subsequent resolution to an issue with packing/handling was handled professionally, efficiently and simplistically for my benefit. GREAT JOB and many thanks.
The folds in the filter were bunched up at one end and spread out across the rest of the filter. I'm sure this will effect the effectiveness of the filter.