here something to think about.... i was at BIG W, comparing Z145A's and i noticed that the Valvoline for 9$ was exactly the same as the $3.95 cheaper brand...forget the name, but was in a black box, bottom shelf.... one of those brands which you never heard of,...
i actually compared the outside casing, the hole size, the way the insides are pressed together, the inside of the filter material, you can see the holes and inside guts when you look in the light...and let me tell you guys...absolutely exact,,,,... made in PRC....peoples republic of china....the only difference was the colour...this cheap one was black.... it's funny becuae i remembered that the valvoline used to be a korean product a few years back when i drove a charade.
anyway, i compared the ryco, and there is nothing like it. In the inside the holes are cut differently, and they are more like 'slits', heaps of them, rather than holes. Cost 12$....
I also looked at a 'cooper' brand, and there is no clones, made in korea, sealed with plastic, looks good too.
anyway, somehting to think about.