Originally Posted By: bullwinkle
No, they "use synthetic fibers", code words for a blend, if they were full synthetic the media would be wire backed. Still a good filter, though.
+1
M1 and Wix filters are both synthetic over paper. They are both excellent filters. M1 is a bit more efficient, Wix is a few dollars cheaper.
As to which is 'better', I think it depends on the application. Same with capacity - depends on the application IMO.