Lyman Pro Trim Dies are made in the USA to Lyman’s highest quality standards. Made from stainless steel for a lifetime of use. Pro Trim Dies are threaded on the bottom in 7/8-14 to fit all Lyman Mark 7 and all other reloading presses on the market. The top thread is 13/16-20 for use with Lyman’s new press mounted trimmer or many of the other popular press mounted trimmers on the market