The conveniently packaged Tipton 13-piece caliber-specific set of Best Bore Brushes means that you always have the right brush at hand. Contained in a durable, hinged box with marked cavities, its easy to select the correct Bore Brush for your particular application. Because they are caliber specific, you can be assured of an optimum fit to your firearms bore for efficient and thorough cleaning. 17 to .45 Cal. All brushes have 8-32 threads (.17 and .20 Cal have 5-40 threads and is a standard bore brush. Features: 13 piece caliber specific set of best bore brushes Contained in a durable, hinged box with marked cavities Contains .17 to .45 caliber Jags have 8-32 threads 0.17 and 0.20 caliber have 5-40 threads