Otis brushes incorporate a proprietary Tufcor core wire, offering exceptional corrosion resistance and a tighter twist that ensures superior bristle retention and extended brush life. Specifically designed to clean 6mm, .243, .250, and .257 caliber firearms, these brushes are 2 inches in length and fit 8-32 threaded cleaning rods. Each set includes one nylon brush and one bronze brush, providing versatility for thorough cleaning whether you need gentle or rigorous maintenance. Trust Otis brushes to keep your firearms pristine with their reliable and durable construction.