It’s called a Gano filter http://autocoolantfilter.com/

I highly recommend. I’m running a crate engine and you’d think it would be clean. WRONG. The amount of casting material, gasket pieces and general debris is amazing. And that is a new engine. Old engines, even if supposedly cleaned have more residue. ALL engines should run Gano filters. Especially after installation.

The Gano filter in my crate engine stays pretty clean now that the engine has about 12K miles.