These are a 4 inch filter but are in fact about 3 and 5/8 inches. So as a replacement for a Honeywell 4 inch filter which measures 4 plus inches, it leaves something to be desired.
I bought the medium quality.I can see lots of daylight thru the pleat area I would say holes. Havent installed just put last filter a furnace install company had made for me in Silicon Valley. Also side by side with old filter half inch wider..will see and get back in future.