Recently, Testand Corporation conducted an ISO standards test on automotive air filters which can be viewed at this link: http://www.dieselbombers.com/chevrol...r-testing.html. All I can say is this explains in detail the reason for

(Arlen) SPICER wrote,

“Now that I am not doing the tests and my objectivity is not necessary, let me explain my motivation. The reason I started this crusade was that I was seeing people spend a lot of money on aftermarket filters based on the word of a salesperson or based on the misleading, incomplete or outright deceiving information printed on boxes and in sales literature. Gentlemen and Ladies, Marketing and the lure of profit is VERY POWERFUL!