You were referencing paper filter but the correct term is "paper media". That is the Stock OEM replacement (Purolator), all other aftermarket brands such as K&N and AEM use a cotton bound oil impregnated media, which you can "recharge" and clean yourself.... hence it is able to stop dust particulates. Therefore, hence it is much better and flows better and introduces cleaner air into the engine. All the aftermarket companies are pretty much using the same technology. I remember when K&N where the only boys in town, after their patent expired, you seen so many other companies introduce "their" own renditions. but truthfully, it is all the same technology, its just that K&N was int he game first and longer.