A high quality brass bore brush made by Pedersoli. .54 Cal. 10 x 32 Male Thread. Brass is a softer metal and is easier on the rifling of a barrel. This bore brush is for the discerning shooter who has custom made barrel or any barrel and desires to maintain it like it was still brand new. A bore brush is one of the best tools to remove a lot of fouling out of a barrel. A good investment to keep any barrel in the best condition possible!