The 10 nominal Micron Rating is the problem with the NAPA/Wix version. They do not offer any other version that has a lower micron rating. I have found as well as Diesel911 that other manufactures of the same type of filter have different micron ratings. Because of this, Diesel911 and I think that all filters should have a micron rating printed on the filter somewhere to avoid confusion.
Here is the Baldwin screen print from the rep on compatable filters that use the same casings and gasket design.
