The Pro-Shot Patriot Bore Brushed are stiff heavy duty, red, white, and blue nylon brushes exclusively made by Pro-Shot. They will not flatten like standard brass bristle brushes which helps to remove more fouling. The bristles also resist ammonia and oil based cleaners.Featuresa Stiff heavy duty red, white, and blue nylon bristlesa Will not flatten like standard brass bristles brushesa Manufactured with solid Brass Core & Couplinga Stiff Colored bristles resist ammonia and oil-based cleanersa Standard American #5/16-27