I do not have any information on the efficiency of these filters. Unfortunately, it appears that these filters, which are also Nissan filters, do not publish much information regarding the matter. I used to be very concerned about efficiency rate years ago but after watching professional mechanics recommending OEM filters over after market ones, I do not worry much. I rather use the OEM filters which are specifically made for the vehicle you own. I have seen videos showing Toyota vehicles, for example, that have only used OEM filters, which are not well known for their efficiency, and yet those engines last 300,000 miles or more. The Mitsubishi filters are made in Japan and appear to be well constructed. They have small holes in the inner core instead of louvers which I, and others, prefer as there is no concern as with louvers which may not all be fully open. Also, if your car is under warranty, I believe it is better to use OEM filters to avoid any potential issues with a warranty claim. Hope this helps.