Luberfiner XL imperial sereis will say it on the filter. They are a very close to a Amsoil filter in efficiency, 50% * 5 microns ans 98% at 20 microns. But there regular filters are on par with brands like WIX and Bosch, they are not as heavy duty as Baldwin or Fleetguard except there XL series, but still good filters.
You really can't miss them. But they only come in a limited amount of sizes.
I keep a stock of them for the other half of my bypass oil filtration set up.
I did a little search looks like W&L sells them
Last edited by dvldoc; March 18th, 2012 at 12:25 AM.