I have Fitertrons in my other two Gretsch so I thought I would try a set of Supertrons in my 57RI Duo Jet.
I ordered them in chrome covers in the Dyna housing. As usual the quality of the build was first class and they were shipped fairly quickly.
Do they sound like a Filtertron? Well yes but they have a smoother, less clunky tone and have a throaty bottom end and a little more midrange. I love'em and they look cool too.