FYi, I did have an opportunity to eyeball both a M1C-251 and NAPA Synthetic 47047, sorry no pics. The M1 appeared to be a twin to the TRD except for the media (steel center tube and rubber o-rings inserted into the metal endcaps). The WIX/NAPA appeared to have copied the Fram XG design except for different wire backed media (no center tube and it had plastic endcaps just like the Fram). The M1 was made in the USA and the WIX/NAPA in Poland.