You cannot hide that there is almost no filtering material in a cartridge type filter. So Fram cleans up their act with them.

With the actual low cost of the filtering medium. I often wondered if every last penny of profit was that important to them on their spin on filters. I estimated there was only 10 to 20 percent of the filtering material in comparison to decent German filters with Fram.

I think others also play the same game. They rightly assume few will ever cut them open and examine them.