A filter for use in engines or transmissions is provided comprising an inlet-side cover having a wave-like region along the periphery of the inlet-side cover, an outlet-side cover having a wave-like region along the periphery of the outlet-side cover where the outlet-side cover wave-like region is in a complementary alignment with the inlet-side cover wave-like region and filter media fixed in a non-planar configuration between the wave-like regions of the inlet-side and outlet-side covers.